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122-691: The four-minute Amberol cylinder made its debut in 1908. Amberols were made of a fragile, black, wax-like compound which was harder than the original 1902 black wax. This Amberol wax was also used for 2-minute standard records from 1908 until the Blue Amberol appeared in 1912. The introduction of the Amberol started a resurgence of interest in cylinder records, but problems soon became apparent. Amberols crack rather easily and could break during playback. Amberols often shattered when they broke, unlike some kinds of 2-minute wax cylinders that would simply crack into

244-584: A bucket of plaster as part of a school art project. Plaster that contains powdered silica or asbestos presents health hazards if inhaled repeatedly. Asbestos is a known irritant when inhaled and can cause cancer, especially in people who smoke, and inhalation can also cause asbestosis . Inhaled silica can cause silicosis and (in very rare cases) can encourage the development of cancer . Persons working regularly with plaster containing these additives should take precautions to avoid inhaling powdered plaster, cured or uncured. Sapphire Sapphire

366-468: A certificate from an independent gemological laboratory attesting to "no evidence of heat treatment". Yogo sapphires do not need heat treating because their cornflower blue color is attractive out of the ground; they are generally free of inclusions , and have high uniform clarity. When Intergem Limited began marketing the Yogo in the 1980s as the world's only guaranteed untreated sapphire, heat treatment

488-425: A detergent agent (such as sodium dodecylbenzene sulfonate ). Plaster may also be used to create complex detailing for use in room interiors. These may be geometric (simulating wood or stone) or naturalistic (simulating leaves, vines, and flowers). These are also often used to simulate wood or stone detailing found in more substantial buildings. In modern days this material is also used for false ceiling . In this,

610-399: A dominant red body color. This is generally caused by traces of chromium (Cr ) substituting for the (Al ) ion in the corundum structure. The color can be modified by both iron and trapped hole color centers. Unlike localized ("intra-atomic") absorption of light, which causes color for chromium and vanadium impurities, blue color in sapphires comes from intervalence charge transfer, which is

732-399: A few pieces. Another problem was that wax Amberols wore out too quickly. Some Amberols mistracked or played with a wavering pitch due to uneven shrinkage during the manufacturing process. By 1912, the shortcomings of the wax Amberol were obvious. Edison, who did not want to pay royalties to Thomas B. Lambert for his celluloid cylinder patent, eventually bought it and changed production over to

854-403: A fire. Early versions of protective plasters often contain asbestos fibres, which since have been outlawed in many industrialized nations. Recent plasters for fire protection either contain cement or gypsum as binding agents as well as mineral wool or glass fiber to add mechanical strength. Vermiculite , polystyrene beads or chemical expansion agents are often added to decrease the density of

976-458: A flattened fishtail weight that was recalled almost immediately as being "unsatisfactory", was refitted with the Model "M" reproducer with flip-over 2 and 4-minute sapphire styli for playing wax cylinders. There is at least one known example of an early Model M reproducer also fitted with a flattened fishtail weight. Upon the introduction of Blue Amberols in 1912, the M reproducer was supplanted by

1098-455: A hand-made and pleasing textured alternative to machine-made modern substrate finishes. But clay plaster finishes are rare and fleeting. According to Martin Weaver, "Many of North America's historic building interiors … are all too often … one of the first things to disappear in the frenzy of demolition of interiors which has unfortunately come to be a common companion to 'heritage preservation' in

1220-467: A lime and sand mortar to provide a weather proof seal to protect from water penetration. This allowed a rendering of clay plaster and setting coat of thin lime and fine sand on exterior-walled rooms. Split lath was nailed with square cut lath nails, one into each framing member. With hand split lath the plasterer had the luxury of making lath to fit the cavity being plastered. Lengths of lath two to six foot are not uncommon at Economy Village. Hand split lath

1342-410: A lot of strain due to the high thermal gradient between the flame and surrounding air. To release this strain, the now finger-shaped crystal will be tapped with a chisel to split it into two halves. Due to the vertical layered growth of the crystal and the curved upper growth surface (which starts from a drop), the crystals will display curved growth lines following the top surface of the boule. This

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1464-439: A maximum playing time of about 4 minutes and 45 seconds and play at the standard post-1902 cylinder speed of 160 rpm. Like the preceding black wax Amberols, they provide twice the playing time of 2-minute cylinders by using a finer groove with a pitch of 200 lines per inch instead of 100. They cannot be played on older machines set up to play only the earlier standard 2 minute cylinders, as both wax and celluloid Amberols require

1586-622: A mixture of suitable plaster, sand, Portland cement and water which is normally applied to masonry interiors and exteriors to achieve a smooth surface. Interior surfaces sometimes receive a final layer of gypsum plaster. Walls constructed with stock bricks are normally plastered while face brick walls are not plastered. Various cement-based plasters are also used as proprietary spray fireproofing products. These usually use vermiculite as lightweight aggregate. Heavy versions of such plasters are also in use for exterior fireproofing, to protect LPG vessels, pipe bridges and vessel skirts. Cement plaster

1708-471: A patient's head and neck, and liquid plaster is used to fill the impression and produce a plaster bust. The transparent material polymethyl methacrylate (Plexiglas, Perspex) is then vacuum formed over this bust to create a clear face mask which will hold the patient's head steady while radiation is being delivered. In dentistry, plaster is used for mounting casts or models of oral tissues. These diagnostic and working models are usually made from dental stone,

1830-454: A plaster positive was desired this would be constructed or cast to form a durable image artwork. As a model for stonecutters this would be sufficient. If intended for producing a bronze casting the plaster positive could be further worked to produce smooth surfaces. An advantage of this plaster image is that it is relatively cheap; should a patron approve of the durable image and be willing to bear further expense, subsequent molds could be made for

1952-410: A plaster secondary support. Some, like Michelangelo's Sistine Chapel ceiling , are executed in fresco , meaning they are painted on a thin layer of wet plaster, called intonaco ; the pigments sink into this layer so that the plaster itself becomes the medium holding them, which accounts for the excellent durability of fresco. Additional work may be added a secco on top of the dry plaster, though this

2074-407: A positive model of the limb and used in fabricating the final medical device. In addition, dentures (false teeth) are made by first taking a dental impression using a soft, pliable material that can be removed from around the teeth and gums without loss of fidelity and using the impression to creating a wax model of the teeth and gums. The model is used to create a plaster mold (which is heated so

2196-400: A primary advantage of the material is that it is resistant to a fire within a room and so can assist in reducing or eliminating structural damage or destruction provided the fire is promptly extinguished. Lime plaster is used for frescoes , where pigments , diluted in water, are applied to the still wet plaster. USA and Iran are the main plaster producers in the world. Cement plaster is

2318-400: A rate of 1 to 100 mm per hour. The alumina crystallizes on the end, creating long carrot-shaped boules of large size up to 200 kg in mass. Synthetic sapphire is also produced industrially from agglomerated aluminum oxide, sintered and fused (such as by hot isostatic pressing ) in an inert atmosphere, yielding a transparent but slightly porous polycrystalline product. In 2003,

2440-420: A remarkable property of setting into a hard mass on wetting with water. CaSO 4 ⋅ 1 2 H 2 O + 1 1 2 H 2 O ⟶ CaSO 4 ⋅ 2 H 2 O {\displaystyle {\ce {CaSO4.1/2H2O + 1 1/2H2O -> CaSO4.2H2O}}} Plaster of Paris

2562-503: A respected laboratory such as GIA , Lotus Gemology , or SSEF , is often required by buyers before they will make a purchase. Sapphires in colors other than blue are called "fancy" sapphires. "Parti sapphire" is used for multicolor stones with zoning of different colors (hues), but not different shades. Fancy sapphires are found in yellow, orange, green, brown, purple, violet, and practically any other hue. Gemstone color can be described in terms of hue , saturation , and tone . Hue

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2684-431: A rigid denture base. Moreover, in dentistry there are 5 types of gypsum products depending on their consistency and uses: 1) impression plaster (type 1), 2) model plaster (type 2), dental stones (types 3, 4 and 5) In orthotics and prosthetics, plaster bandages traditionally were used to create impressions of the patient's limb (or residuum). This negative impression was then, itself, filled with plaster of Paris, to create

2806-459: A similar way. The plaster is manufactured as a dry powder and is mixed with water to form a stiff but workable paste immediately before it is applied to the surface. The reaction with water liberates heat through crystallization and the hydrated plaster then hardens. Plaster can be relatively easily worked with metal tools and sandpaper and can be moulded, either on site or in advance, and worked pieces can be put in place with adhesive . Plaster

2928-523: A sledge. When small enough, a froe and mallet were used to split away narrow strips of lath. Farm animals provided hair and manure for the float coat of plaster. Fields of wheat and grains provided straw and hay to reinforce the clay plaster. But there was no uniformity in clay plaster recipes. Manure provides fiber for tensile strength as well as protein adhesive. Unlike casein used with lime plaster, hydrogen bonds of manure proteins are weakened by moisture. With braced timber-framed structures clay plaster

3050-446: A smaller stylus tip to fit the finer groove and the worm-gear which moves the stylus over the surface of the cylinder must turn at a different rate. Thomas A. Edison, Inc . sold kits with gear assemblies and reproducers that could be installed by the owner of an older Edison machine so that both standard and 4-minute records could be played. The Edison company also marketed new models capable of playing both. With these combination machines

3172-416: A stronger, harder and denser derivative of plaster which is manufactured from gypsum under pressure. Plaster is also used to invest and flask wax dentures, the wax being subsequently removed by "burning out," and replaced with flowable denture base material. The typically acrylic denture base then cures in the plaster investment mold. Plaster investments can withstand the high heat and pressure needed to ensure

3294-540: A thin but tough blue-tinted celluloid reinforced with a plaster of Paris core. The introduction of these "Blue Amberols" helped to hike cylinder sales. The early Blue Amberol releases offered excellent audio quality for their era — better, in fact, than later issues, because from January 1915 onward Thomas A. Edison, Inc. , which had been concentrating its efforts on improving the quality of Diamond Disc phonograph records, began to release cylinders which were acoustically dubbed from Diamond Discs. The dubbing technique used

3416-417: A variety of shades. Corundum that contains extremely low levels of chromophores is near colorless. Completely colorless corundum generally does not exist in nature. If trace amounts of iron are present, a very pale yellow to green color may be seen. However, if both titanium and iron impurities are present together, and in the correct valence states, the result is a blue color. Intervalence charge transfer

3538-521: Is a building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements. In English, "plaster" usually means a material used for the interiors of buildings, while "render" commonly refers to external applications. The term stucco refers to plasterwork that is worked in some way to produce relief decoration, rather than flat surfaces. The most common types of plaster mainly contain either gypsum , lime , or cement , but all work in

3660-590: Is a mixture of clay , sand and water often with the addition of plant fibers for tensile strength over wood lath . Clay plaster has been used around the world at least since antiquity. Settlers in the American colonies used clay plaster on the interiors of their houses: "Interior plastering in the form of clay antedated even the building of houses of frame, and must have been visible in the inside of wattle filling in those earliest frame houses in which … wainscot had not been indulged. Clay continued in use long after

3782-525: Is a precious gemstone , a variety of the mineral corundum , consisting of aluminium oxide ( α- Al 2 O 3 ) with trace amounts of elements such as iron , titanium , cobalt , lead , chromium , vanadium , magnesium , boron , and silicon . The name sapphire is derived from the Latin word sapphirus , itself from the Greek word sappheiros ( σάπφειρος ), which referred to lapis lazuli . It

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3904-442: Is a process that produces a strong colored appearance at a low percentage of impurity. While at least 1% chromium must be present in corundum before the deep red ruby color is seen, sapphire blue is apparent with the presence of only 0.01% of titanium and iron. Colorless sapphires, which are uncommon in nature, were once used as diamond substitutes in jewelry, and are presently used as accent stones. The most complete description of

4026-459: Is a specific change in energy for the electron, and electromagnetic energy is absorbed. The wavelength of the energy absorbed corresponds to yellow light. When this light is subtracted from incident white light, the complementary color blue results. Sometimes when atomic spacing is different in different directions, there is resulting blue-green dichroism . Purple sapphires contain trace amounts of chromium and iron plus titanium and come in

4148-486: Is a type of sapphire that exhibits a star-like phenomenon known as asterism ; red stones are known as "star rubies". Star sapphires contain intersecting needle-like inclusions following the underlying crystal structure that causes the appearance of a six-rayed "star"-shaped pattern when viewed with a single overhead light source. The inclusion is often the mineral rutile , a mineral composed primarily of titanium dioxide . The stones are cut en cabochon , typically with

4270-462: Is accompanied by a slight expansion of volume. It is used in making casts for statues, toys , and more. The initial matrix consists mostly of orthorhombic crystals: the kinetic product. Over the next 72 hours, the rhombic crystals give way to an interlocking mass of monoclinic crystal needles, and the plaster increases in hardness and strength. If plaster or gypsum is heated to between 130 °C (266 °F) and 180 °C (350 °F), hemihydrate

4392-439: Is added to the flame, causing it to burn slightly hotter. This expands the growing crystal laterally. At the same time, the pedestal is lowered at the same rate that the crystal grows vertically. The alumina in the flame is slowly deposited, creating a teardrop shaped " boule " of sapphire material. This step is continued until the desired size is reached, the flame is shut off and the crystal cools. The now elongated crystal contains

4514-494: Is called padparadscha . Significant sapphire deposits are found in Australia , Afghanistan , Cambodia , Cameroon , China ( Shandong ), Colombia , Ethiopia , India Jammu and Kashmir ( Padder , Kishtwar ), Kenya , Laos , Madagascar , Malawi , Mozambique , Myanmar ( Burma ), Nigeria , Rwanda , Sri Lanka , Tanzania , Thailand , United States ( Montana ) and Vietnam . Sapphire and rubies are often found in

4636-451: Is common practice to heat natural sapphires to improve or enhance their appearance. This is done by heating the sapphires in furnaces to temperatures between 800 and 1,800 °C (1,470 and 3,270 °F) for several hours, or even weeks at a time. Different atmospheres may be used. Upon heating, the stone becomes bluer in color, but loses some of the rutile inclusions (silk). When high temperatures (1400 °C+) are used, exsolved rutile silk

4758-525: Is commonly based on the reaction of gypsum plaster with water, where the water is selectively applied by the inkjet head. The chemical reaction that occurs when plaster is mixed with water is exothermic . When plaster sets, it can reach temperatures of more than 60 °C (140 °F) and, in large volumes, can burn the skin. In January 2007, a secondary school student in Lincolnshire , England sustained third-degree burns after encasing her hands in

4880-428: Is commonly understood as the " color " of the gemstone. Saturation refers to the vividness or brightness of the hue, and tone is the lightness to darkness of the hue. Blue sapphire exists in various mixtures of its primary (blue) and secondary hues, various tonal levels (shades) and at various levels of saturation (vividness). Blue sapphires are evaluated based upon the purity of their blue hue. Violet and green are

5002-409: Is dissolved and it becomes clear under magnification. The titanium from the rutile enters solid solution and thus creates with iron the blue color. The inclusions in natural stones are easily seen with a jeweler's loupe . Evidence of sapphire and other gemstones being subjected to heating goes back at least to Roman times. Un-heated natural stones are somewhat rare and will often be sold accompanied by

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5124-456: Is formed, which will also re-form as gypsum if mixed with water. On heating to 180 °C (350 °F), the nearly water-free form, called γ-anhydrite (CaSO 4 · n H 2 O where n = 0 to 0.05) is produced. γ-anhydrite reacts slowly with water to return to the dihydrate state, a property exploited in some commercial desiccants . On heating above 250 °C (480 °F), the completely anhydrous form called β-anhydrite or dead burned plaster

5246-436: Is formed. Lime plaster is a mixture of calcium hydroxide and sand (or other inert fillers). Carbon dioxide in the atmosphere causes the plaster to set by transforming the calcium hydroxide into calcium carbonate ( limestone ). Whitewash is based on the same chemistry. To make lime plaster, limestone (calcium carbonate) is heated above approximately 850 °C (1600 °F) to produce quicklime (calcium oxide). Water

5368-735: Is generally less durable. Plaster (often called stucco in this context) is a far easier material for making reliefs than stone or wood, and was widely used for large interior wall-reliefs in Egypt and the Near East from antiquity into Islamic times (latterly for architectural decoration, as at the Alhambra ), Rome, and Europe from at least the Renaissance, as well as probably elsewhere. However, it needs very good conditions to survive long in unmaintained buildings – Roman decorative plasterwork

5490-557: Is heavily tilted to the red end of the spectrum, thus tipping the balance to red. Color-change sapphires colored by the Cr + Fe/Ti chromophores generally change from blue or violet-blue to violet or purple. Those colored by the V chromophore can show a more pronounced change, moving from blue-green to purple. Certain synthetic color-change sapphires have a similar color change to the natural gemstone alexandrite and they are sometimes marketed as "alexandrium" or "synthetic alexandrite". However,

5612-432: Is in contrast to natural corundum crystals, which feature angular growth lines expanding from a single point and following the planar crystal faces. Chemical dopants can be added to create artificial versions of the ruby, and all the other natural colors of sapphire, and in addition, other colors never seen in geological samples. Artificial sapphire material is identical to natural sapphire, except it can be made without

5734-490: Is mainly known from Pompeii and other sites buried by ash from Mount Vesuvius . Plaster may be cast directly into a damp clay mold. In creating this piece molds (molds designed for making multiple copies) or waste molds (for single use) would be made of plaster. This "negative" image, if properly designed, may be used to produce clay productions, which when fired in a kiln become terra cotta building decorations, or these may be used to create cast concrete sculptures. If

5856-477: Is not uniform like sawn lath. The straightness or waviness of the grain affected the thickness or width of each lath, and thus the spacing of the lath. The clay plaster rough coat varied to cover the irregular lath. Window and door trim as well as the mudboard (baseboard) acted as screeds. With the variation of the lath thickness and use of coarse straw and manure, the clay coat of plaster was thick in comparison to later lime-only and gypsum plasters. In Economy Village,

5978-594: Is often used as an artistic material for casting. Plaster is also commonly spread over an armature (form), made of wire mesh, cloth, or other materials; a process for adding raised details. For these processes, limestone or acrylic based plaster may be employed, known as stucco. Products composed mainly of plaster of Paris and a small amount of Portland cement are used for casting sculptures and other art objects as well as molds. Considerably harder and stronger than straight plaster of Paris, these products are for indoor use only as they degrade in moist conditions. Plaster

6100-533: Is produced by heating gypsum to about 120–180 °C (248–356 °F) in a kiln: CaSO 4 ⋅ 2 H 2 O ⟶ heat CaSO 4 ⋅ 1 2 H 2 O + 1 1 2 H 2 O ↑ {\displaystyle {\ce {CaSO4.2H2O {\overset {heat}{{}->{}}}{CaSO4.1/2H2O}+ 1\!1/2 H2O ^}}} (released as steam). Plaster of Paris has

6222-416: Is required of any mode of enhancement that has a significant effect on the gem's value. There are several ways of treating sapphire. Heat-treatment in a reducing or oxidizing atmosphere (but without the use of any other added impurities) is commonly used to improve the color of sapphires, and this process is sometimes known as "heating only" in the gem trade. In contrast, however, heat treatment combined with

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6344-419: Is stored in moisture -proof containers, because the presence of moisture can cause slow setting of plaster of Paris by bringing about its hydration, which will make it useless after some time. When the dry plaster powder is mixed with water, it rehydrates over time into gypsum. The setting of plaster slurry starts about 10 minutes after mixing and is complete in about 45 minutes. The setting of plaster of Paris

6466-455: Is suitable for finishing rather than load-bearing, and when thickly applied for decoration may require a hidden supporting framework. Forms of plaster have several other uses. In medicine, plaster orthopedic casts are still often used for supporting set broken bones. In dentistry, plaster is used to make dental models by pouring the material into dental impressions . Various types of models and moulds are made with plaster. In art, lime plaster

6588-404: Is the birthstone for September and the gem of the 45th anniversary . A sapphire jubilee occurs after 65 years. Sapphire is one of the two gem-varieties of corundum , the other being ruby (defined as corundum in a shade of red). Although blue is the best-known sapphire color, it occurs in other colors, including gray and black, and also can be colorless. A pinkish orange variety of sapphire

6710-402: Is the traditional matrix for fresco painting; the pigments are applied to a thin wet top layer of plaster and fuse with it so that the painting is actually in coloured plaster. In the ancient world, as well as the sort of ornamental designs in plaster relief that are still used, plaster was also widely used to create large figurative reliefs for walls, though few of these have survived. Plaster

6832-421: Is then added to produce slaked lime (calcium hydroxide), which is sold as a wet putty or a white powder. Additional water is added to form a paste prior to use. The paste may be stored in airtight containers. When exposed to the atmosphere, the calcium hydroxide very slowly turns back into calcium carbonate through reaction with atmospheric carbon dioxide, causing the plaster to increase in strength. Lime plaster

6954-709: Is thought to be the third-largest star sapphire, and is currently on display at the American Museum of Natural History in New York City . The 182-carat Star of Bombay , mined in Sri Lanka and located in the National Museum of Natural History in Washington, D.C. , is another example of a large blue star sapphire. The value of a star sapphire depends not only on the weight of the stone, but also

7076-476: Is to find lime, bricks, clay, stone, haire, together with laborers and workmen." Records of the New Haven colony in 1641 mention clay and hay as well as lime and hair also. In German houses of Pennsylvania the use of clay persisted. Old Economy Village is one such German settlement. The early Nineteenth-Century utopian village in present-day Ambridge , Pennsylvania, used clay plaster substrate exclusively in

7198-400: Is to replace conventional gypsum plasters in cases where the temperature can get too high for gypsum plaster to stay on the wall or ceiling. An example of a heat-resistant plaster composition is a mixture of Portland cement , gypsum, lime, exfoliated insulating aggregate ( perlite and vermiculite or mica ), phosphate shale , and small amounts of adhesive binder (such as Gum karaya ), and

7320-538: Is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on the locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewelry . They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules . Because of

7442-503: Is used. The walls are painted with the plaster which (in some countries) is nothing but calcium carbonate. After drying the calcium carbonate plaster turns white and then the wall is ready to be painted. Elsewhere in the world, such as the UK, ever finer layers of plaster are added on top of the plasterboard (or sometimes the brick wall directly) to give a smooth brown polished texture ready for painting. Mural paintings are commonly painted onto

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7564-401: Is widely used as a support for broken bones; a bandage impregnated with plaster is moistened and then wrapped around the damaged limb, setting into a close-fitting yet easily removed tube, known as an orthopedic cast . Plaster is also used in preparation for radiotherapy when fabricating individualized immobilization shells for patients. Plaster bandages are used to construct an impression of

7686-499: The Ediphone that were essentially long Blue Amberols and remained in production for many years after the demise of the cylinder format as an entertainment medium. Edison Blue Amberols are made of celluloid on a molded plaster core. The celluloid surface is able to withstand hundreds of playings with only a moderate increase in surface noise if played on a well-maintained machine with a stylus in good condition. Blue Amberols have

7808-633: The Star of India , The Star of Adam and the Star of Bombay originate from Sri Lankan mines. Madagascar is the world leader in sapphire production (as of 2007) specifically its deposits in and around the town of Ilakaka . Prior to the opening of the Ilakaka mines, Australia was the largest producer of sapphires (such as in 1987). In 1991 a new source of sapphires was discovered in Andranondambo, southern Madagascar. The exploitation started in 1993, but

7930-566: The chromium chromophore that creates the red color of ruby, combined with the iron + titanium chromophore that produces the blue color in sapphire. A rarer type, which comes from the Mogok area of Myanmar, features a vanadium chromophore, the same as is present in Verneuil synthetic color-change sapphire. Virtually all gemstones that show the "alexandrite effect" (color change or ' metamerism ') show similar absorption/transmission features in

8052-665: The 12.00 carat Cartier sapphire ring at US$ 193,975 per carat, then with a 17.16 carat sapphire at US$ 236,404, and again in June 2015 when the per-carat auction record was set at US$ 240,205. At present, the world record price-per-carat for sapphire at auction is held by a sapphire from Kashmir in a ring, which sold in October 2015 for approximately US$ 242,000 per carat ( HK$ 52,280,000 in total, including buyer's premium, or more than US$ 6.74 million). Sapphires can be treated by several methods to enhance and improve their clarity and color. It

8174-559: The Amberola line was simplified in both mechanical and cabinet design, resulting in the 4-minute-only Amberola 30, 50, and 75, each model number indicating the initial retail price in dollars. They were equipped with the Diamond C reproducer. The 4-minute-only external horn Opera (later renamed Concert) model of 1911-1912, which used the same mechanism as the IB and III, was initially fitted with

8296-563: The Diamond A reproducer, which was designed for playing only celluloid cylinders. Its small-tipped conical diamond stylus and increased stylus pressure would seriously damage wax cylinders. External horn Edison phonographs were available with the Diamond B reproducer. Several other Amberola models less expensive than the IA (and later the 4-minute-only IB and III) were available, such as the V, VI, and X. After an Edison factory fire in December 1914,

8418-524: The French chemist Auguste Verneuil announced a process for producing synthetic ruby crystals. In the flame-fusion ( Verneuil process ), fine alumina powder is added to an oxyhydrogen flame , and this is directed downward against a ceramic pedestal. Following the successful synthesis of ruby, Verneuil focused his efforts on sapphire. Synthesis of blue sapphire came in 1909, after chemical analyses of sapphire suggested to Verneuil that iron and titanium were

8540-485: The Model L reproducer, which had an elliptical sapphire stylus for playing wax Amberols, but after the introduction of Blue Amberols it shipped with the Diamond A reproducer. The "Amberol" plastic is on a plaster of Paris core. This core is proving to be problematic for the long-term survival of Blue Amberol Records, as the plaster often tends to expand over the decades, especially if exposed to moisture or kept in humid conditions. In moderate cases, swollen plaster can make

8662-443: The adoption of laths and brick filling for the frame." Where lime was not easily accessible it was rationed and usually substituted with clay as a binder. In Martin E. Weaver 's seminal work he says, "Mud plaster consists of clay or earth which is mixed with water to give a 'plastic' or workable consistency. If the clay mixture is too plastic it will shrink, crack and distort on drying. Sand, fine gravels and fibres were added to reduce

8784-698: The area of Franklin, North Carolina . The sapphire deposits of Kashmir are well known in the gem industry, although their peak production took place in a relatively short period at the end of the nineteenth and early twentieth centuries. These deposits are located in the Paddar Valley of the Jammu region of Jammu and Kashmir in India. They have a superior vivid blue hue, coupled with a mysterious and almost sleepy quality, described by some gem enthusiasts as ‘blue velvet”. Kashmir-origin contributes meaningfully to

8906-591: The biggest problem the Yogo mine faced was not competition from heated sapphires, but the fact that the Yogo stones could never produce quantities of sapphire above one carat after faceting. As a result, it has remained a niche product, with a market that largely exists in the US. Lattice ('bulk') diffusion treatments are used to add impurities to the sapphire to enhance color. This process was originally developed and patented by Linde Air division of Union Carbide and involved diffusing titanium into synthetic sapphire to even out

9028-415: The blue color. It was later applied to natural sapphire. Today, titanium diffusion often uses a synthetic colorless sapphire base. The color layer created by titanium diffusion is extremely thin (less than 0.5 mm). Thus repolishing can and does produce slight to significant loss of color. Chromium diffusion has been attempted, but was abandoned due to the slow diffusion rates of chromium in corundum. In

9150-466: The body color, visibility, and intensity of the asterism. The color of the stone has more impact on the value than the visibility of the star. Since more transparent stones tend to have better colors, the most expensive star stones are semi-transparent "glass body" stones with vivid colors. On 28 July 2021, the world's largest cluster of star sapphires, weighing 510 kg (1,120 lb), was unearthed from Ratnapura, Sri Lanka. This star sapphire cluster

9272-458: The brick and wood frame high architecture of the Feast Hall, Great House and other large and commercial structures as well as in the brick, frame and log dwellings of the society members. The use of clay in plaster and in laying brickwork appears to have been a common practice at that time not just in the construction of Economy village when the settlement was founded in 1824. Specifications for

9394-433: The cause of the blue color. Verneuil patented the process of producing synthetic blue sapphire in 1911. The key to the process is that the alumina powder does not melt as it falls through the flame. Instead it forms a sinter cone on the pedestal. When the tip of that cone reaches the hottest part of the flame, the tip melts. Thus the crystal growth is started from a tiny point, ensuring minimal strain. Next, more oxygen

9516-1278: The causes of color in corundum extant can be found in Chapter ;4 of Ruby & Sapphire: A Gemologist's Guide (chapter authored by John Emmett, Emily Dubinsky and Richard Hughes). Sapphires are mined from alluvial deposits or from primary underground workings. Commercial mining locations for sapphire and ruby include (but are not limited to) the following countries: Afghanistan , Australia , Myanmar / Burma , Cambodia , China , Colombia , India , Kenya , Laos , Madagascar , Malawi , Nepal , Nigeria , Pakistan , Sri Lanka , Tajikistan , Tanzania , Thailand , United States, and Vietnam . Sapphires from different geographic locations may have different appearances or chemical-impurity concentrations, and tend to contain different types of microscopic inclusions. Because of this, sapphires can be divided into three broad categories: classic metamorphic, non-classic metamorphic or magmatic, and classic magmatic. Sapphires from certain locations, or of certain categories, may be more commercially appealing than others, particularly classic metamorphic sapphires from Kashmir, Burma, or Sri Lanka that have not been subjected to heat-treatment. The Logan sapphire ,

9638-558: The celluloid contract, a combination which can cause the celluloid to split lengthwise very abruptly. The Blue Amberol plastic is nitrocellulose and therefore flammable. Being an organic plastic, celluloid is subject to chemical decomposition, but acute deterioration, as seen in nitrate film reels, has so far rarely if ever been observed in Blue Amberols or other (e.g., Lambert, Albany Indestructible, and US Everlasting ) celluloid cylinders. Plaster of Paris Plaster

9760-459: The center of the star near the top of the dome. Occasionally, twelve-rayed stars are found, typically because two different sets of inclusions are found within the same stone, such as a combination of fine needles of rutile with small platelets of hematite ; the first results in a whitish star and the second results in a golden-colored star. During crystallization, the two types of inclusions become preferentially oriented in different directions within

9882-409: The color penetration is far greater than with titanium diffusion. In some cases, it may penetrate the entire stone. Beryllium-diffused orange sapphires may be difficult to detect, requiring advanced chemical analysis by gemological labs ( e.g. , Gübelin, SSEF , GIA , American Gemological Laboratories (AGL), Lotus Gemology . According to United States Federal Trade Commission guidelines, disclosure

10004-475: The concentrations of fine clay particles which were the cause of the excessive shrinkage." Manure was often added for its fibre content. In some building techniques straw or grass was used as reinforcement. In the Earliest European settlers' plasterwork, a mud plaster was used McKee wrote, of a circa 1675 Massachusetts contract that specified the plasterer, "Is to lath and siele the four rooms of

10126-465: The construction of, "Lock keepers houses on the Chesapeake and Ohio Canal, written about 1828, require stone walls to be laid with clay mortar, excepting 3 inches on the outside of the walls … which (are) to be good lime mortar and well pointed." The choice of clay was because of its low cost, but also the availability. At Economy, root cellars dug under the houses yielded clay and sand (stone), or

10248-445: The creation of a wax image to be used in lost wax casting , a far more expensive process. In lieu of producing a bronze image suitable for outdoor use the plaster image may be painted to resemble a metal image; such sculptures are suitable only for presentation in a weather-protected environment. Plaster expands while hardening then contracts slightly just before hardening completely. This makes plaster excellent for use in molds, and it

10370-470: The crystal, thereby forming two six-rayed stars that are superimposed upon each other to form a twelve-rayed star. Misshapen stars or 12-rayed stars may also form as a result of twinning . The inclusions can alternatively produce a cat's eye effect if the girdle plane of the cabochon is oriented parallel to the crystal's c-axis rather than perpendicular to it. To get a cat's eye, the planes of exsolved inclusions must be extremely uniform and tightly packed. If

10492-690: The deliberate addition of certain specific impurities (e.g. beryllium, titanium, iron, chromium or nickel, which are absorbed into the crystal structure of the sapphire) is also commonly performed, and this process can be known as "diffusion" in the gem trade. However, despite what the terms "heating only" and "diffusion" might suggest, both of these categories of treatment actually involve diffusion processes. The most complete description of corundum treatments extant can be found in Chapter 6 of Ruby & Sapphire: A Gemologist's Guide (chapter authored by John Emmett, Richard Hughes and Troy R. Douthit). In 1902,

10614-448: The dome is oriented in between these two directions, an off-center star will be visible, offset away from the high point of the dome. At 1404.49 carats, The Star of Adam is the largest known blue star sapphire. The gem was mined in the city of Ratnapura, southern Sri Lanka. The Black Star of Queensland , the second largest star sapphire in the world, weighs 733 carats . The Star of India mined in Sri Lanka and weighing 563.4 carats

10736-639: The finished product and increase thermal insulation. One differentiates between interior and exterior fireproofing. Interior products are typically less substantial, with lower densities and lower cost. Exterior products have to withstand harsher environmental conditions. A rough surface is typically forgiven inside of buildings as dropped ceilings often hide them. Fireproofing plasters are losing ground to more costly intumescent and endothermic products, simply on technical merit. Trade jurisdiction on unionized construction sites in North America remains with

10858-543: The flaws that are found in natural stones. The disadvantage of the Verneuil process is that the grown crystals have high internal strains. Many methods of manufacturing sapphire today are variations of the Czochralski process , which was invented in 1916 by Polish chemist Jan Czochralski . In this process, a tiny sapphire seed crystal is dipped into a crucible made of the precious metal iridium or molybdenum , containing molten alumina, and then slowly withdrawn upward at

10980-441: The guise of building rehabilitation." Gypsum plaster, also known as plaster of Paris , is a white powder consisting of calcium sulfate hemihydrate . The natural form of the compound is the mineral bassanite . The name "plaster of Paris" was given because it was originally made by heating gypsum from a large deposit at Montmartre , a hill in the north end of Paris . Gypsum plaster, gypsum powder, or plaster of Paris,

11102-436: The highest premium, although Burma, Sri Lanka, and Madagascar also produce large quantities of fine quality gems. The cost of natural sapphires varies depending on their color, clarity, size, cut , and overall quality. Sapphires that are completely untreated are worth far more than those that have been treated. Geographical origin also has a major impact on price. For most gems of one carat or more, an independent report from

11224-450: The house betwixt the joists overhead with a coat of lime and haire upon the clay; also to fill the gable ends of the house with ricks and plaister them with clay. 5. To lath and plaster partitions of the house with clay and lime, and to fill, lath, and plaister them with lime and haire besides; and to siele and lath them overhead with lime; also to fill, lath, and plaster the kitchen up to the wall plate on every side. 6. The said Daniel Andrews

11346-666: The largest faceted gem-quality blue sapphires in existence. Particolored sapphires (or bi-color sapphires) are those stones that exhibit two or more colors within a single stone. The desirability of particolored or bi-color sapphires is usually judged based on the zoning or location of their colors, the colors' saturation, and the contrast of their colors. Australia is the largest source of particolored sapphires; they are not commonly used in mainstream jewelry and remain relatively unknown. Particolored sapphires cannot be created synthetically and only occur naturally. Pink sapphires occur in shades from light to dark pink, and deepen in color as

11468-411: The latter term is a misnomer: synthetic color-change sapphires are, technically, not synthetic alexandrites but rather alexandrite simulants . This is because genuine alexandrite is a variety of chrysoberyl : not sapphire, but an entirely different mineral from corundum. Large rubies and sapphires of poor transparency are frequently used with suspect appraisals that vastly overstate their value. This

11590-563: The letters A through H, rather than the more usual numbers, were given away with 4-minute conversion kits sold for updating some earlier 2-minute phonographs. There were Blue Amberol instructional records to accompany the Edison School Phonograph, ICS language courses, Blue Amberols for Morse code training, Blue Amberols for the French and German markets, special 2-minute Blue Amberols for the rural Mexican market, and 6-inch-long (15 cm) dictation instruction cylinders for

11712-489: The lime top coats are thin veneers often an eighth inch or less attesting to the scarcity of limestone supplies there. Clay plasters with their lack of tensile and compressive strength fell out of favor as industrial mining and technology advances in kiln production led to the exclusive use of lime and then gypsum in plaster applications. However, clay plasters still exist after hundreds of years clinging to split lath on rusty square nails. The wall variations and roughness reveal

11834-431: The main popular and sacred music series, which began with record number 1501 in 1912 and ended with record number 5719 in 1929, Edison offered a special line of prestigious Concert Blue Amberols of opera arias, light classical pieces, and other "cultured" music performed by "name" artists, later supplanted by the distinctively tinted Royal Purple Amberol cylinders. A set of special wax Amberols or Blue Amberols identified by

11956-480: The mix. Because plaster of Paris sets quickly, "retardants" were used to slow setting time enough to allow workers to mix large working quantities of lime putty plaster. A modern form of this method uses expanded metal mesh over wood or metal structures, which allows a great freedom of design as it is adaptable to both simple and compound curves. Today this building method has been partly replaced with drywall , also composed mostly of gypsum plaster. In both these methods,

12078-406: The most common secondary hues found in blue sapphires. The highest prices are paid for gems that are pure blue and of vivid saturation. Gems that are of lower saturation, or are too dark or too light in tone are of less value. However, color preferences are a personal taste. The 423-carat (84.6 g) Logan sapphire in the National Museum of Natural History , in Washington, D.C. , is one of

12200-403: The nearby Ohio river yielded washed sand from the sand bars; and lime outcroppings and oyster shell for the lime kiln . The surrounding forests of the new village of Economy provided straight grain, old- growth oak trees for lath. Hand split lath starts with a log of straight grained wood of the required length. The log is split into quarters and then smaller and smaller bolts with wedges and

12322-458: The operator needed to adjust a knob or lever that shifted gears and make sure the correct reproducing stylus was in position when switching from one record type to the other. Internal horn Edison phonographs designed to play 4-minute cylinders were called Amberolas. The earliest Amberola model, the 1909 Amberola IA, was equipped with selectable 2 and 4-minute gearing, and after initially being sent out fitted with an unmarked Model "L" reproducer with

12444-403: The plasterers, regardless of whether the plaster is decorative in nature or is used in passive fire protection. Cementitious and gypsum based plasters tend to be endothermic. Fireproofing plasters are closely related to firestop mortars. Most firestop mortars can be sprayed and tooled very well, due to the fine detail work that is required of firestopping. Powder bed and inkjet head 3D printing

12566-400: The powder form is converted in a sheet form and the sheet is then attached to the basic ceiling with the help of fasteners. It is done in various designs containing various combinations of lights and colors. The common use of this plaster can be seen in the construction of houses. Post-construction, direct painting is possible (which is commonly seen in French architecture), but elsewhere plaster

12688-648: The quantity of chromium increases. The deeper the pink color, the higher their monetary value . In the United States, a minimum color saturation must be met to be called a ruby , otherwise the stone is referred to as a pink sapphire . Padparadscha is a delicate, light to medium toned, pink-orange to orange-pink hued corundum , originally found in Sri Lanka , but also found in deposits in Vietnam and parts of East Africa . Padparadscha sapphires are rare;

12810-522: The rarest of all is the totally natural variety, with no sign of artificial treatment. The name is derived from the Sanskrit padma ranga (padma = lotus; ranga = color), a color akin to the lotus flower ( Nelumbo nucifera ). Among the fancy (non-blue) sapphires, natural padparadscha fetch the highest prices. Since 2001, more sapphires of this color have appeared on the market as a result of artificial lattice diffusion of beryllium. A star sapphire

12932-412: The record not fit properly on the phonograph mandrel (this can be fairly easily remedied by gently reaming out the plaster to restore the correct inner diameter) or can warp the cylinder out of round, making it not play properly. In worse cases, the expanding plaster will crack or split the plastic playing surface, rendering the record unusable. Freezing causes any moisture in the plaster to expand but makes

13054-589: The remarkable hardness of sapphires – 9 on the Mohs scale (the third-hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows , wristwatch crystals and movement bearings, and very thin electronic wafers , which are used as the insulating substrates of special-purpose solid-state electronics such as integrated circuits and GaN -based blue LEDs . Sapphire

13176-463: The same geographical settings, but they generally have different geological formations. For example, both ruby and sapphire are found in Myanmar's Mogok Stone Tract, but the rubies form in marble, while the sapphire forms in granitic pegmatites or corundum syenites. Every sapphire mine produces a wide range of quality, and origin is not a guarantee of quality. For sapphire, Jammu and Kashmir receives

13298-412: The transfer of an electron from one transition-metal ion to another via the conduction or valence band . The iron can take the form Fe or Fe , while titanium generally takes the form Ti . If Fe and Ti ions are substituted for Al , localized areas of charge imbalance are created. An electron transfer from Fe and Ti can cause a change in the valence state of both. Because of the valence change, there

13420-506: The value of a sapphire, and most corundum of Kashmir origin can be readily identified by its characteristic silky appearance and exceptional hue. The unique blue appears lustrous under any kind of light, unlike non-Kashmir sapphires which may appear purplish or grayish in comparison. Sotheby's has been in the forefront overseeing record-breaking sales of Kashmir sapphires worldwide. In October 2014, Sotheby's Hong Kong achieved consecutive per-carat price records for Kashmir sapphires – first with

13542-445: The visible spectrum. This is an absorption band in the yellow (~590 nm), along with valleys of transmission in the blue-green and red. Thus the color one sees depends on the spectral composition of the light source. Daylight is relatively balanced in its spectral power distribution (SPD) and since the human eye is most sensitive to green light, the balance is tipped to the green side. However incandescent light (including candle light)

13664-582: The wax melts and flows out) and the denture materials are injected into the mold. After a curing period, the mold is opened and the dentures are cleaned up and polished. Plasters have been in use in passive fire protection , as fireproofing products, for many decades. Gypsum plaster releases water vapor when exposed to flame, acting to slow the spread of the fire, for as much as an hour or two depending on thickness. Plaster also provides some insulation to retard heat flow into structural steel elements, that would otherwise lose their strength and collapse in

13786-416: The year 2000, beryllium diffused "padparadscha" colored sapphires entered the market. Typically beryllium is diffused into a sapphire under very high heat, just below the melting point of the sapphire. Initially ( c.  2000 ) orange sapphires were created, although now the process has been advanced and many colors of sapphire are often treated with beryllium. Due to the small size of the beryllium ion,

13908-431: Was a common building material for wall surfaces in a process known as lath and plaster , whereby a series of wooden strips on a studwork frame was covered with a semi-dry plaster that hardened into a surface. The plaster used in most lath and plaster construction was mainly lime plaster , with a cure time of about a month. To stabilize the lime plaster during curing, small amounts of plaster of Paris were incorporated into

14030-464: Was first introduced in America around 1909 and was often called by the generic name adamant plaster after a prominent manufacturer of the time. The advantages of cement plaster noted at that time were its strength, hardness, quick setting time and durability. Heat-resistant plaster is a building material used for coating walls and chimney breasts and for use as a fire barrier in ceilings. Its purpose

14152-534: Was first used as a building material and for decoration in the Middle East at least 7,000 years ago. In Egypt, gypsum was burned in open fires, crushed into powder, and mixed with water to create plaster, used as a mortar between the blocks of pyramids and to provide a smooth wall facing. In Jericho, a cult arose where human skulls were decorated with plaster and painted to appear lifelike. The Romans brought plaster-work techniques to Europe . Clay plaster

14274-490: Was named " Serendipity Sapphire ". A rare variety of natural sapphire, known as color-change sapphire, exhibits different colors in different light. Color change sapphires are blue in outdoor light and purple under incandescent indoor light, or green to gray-green in daylight and pink to reddish-violet in incandescent light. Color-change sapphires come from a variety of locations, including Madagascar , Myanmar , Sri Lanka and Tanzania . Two types exist. The first features

14396-425: Was non-electronic (the disc phonograph horn played into the cylinder recording horn) until December 1927, when electronic dubbing was introduced. This resulted in a somewhat hollow "dead" sound on the cylinders compared to the original discs. On many dubbed cylinders, when the cylinder's own 160 rpm surface noise is low enough, 80 rpm disc surface noise can be heard starting up shortly before the music begins. Beyond

14518-550: Was not commonly disclosed; by the late 1980s, heat treatment became a major issue. At that time, much of all the world's sapphires were being heated to enhance their natural color. Intergem's marketing of guaranteed untreated Yogos set them against many in the gem industry. This issue appeared as a front-page story in The Wall Street Journal on 29 August 1984 in an article by Bill Richards, Carats and Schticks: Sapphire Marketer Upsets The Gem Industry . However,

14640-613: Was practically abandoned just a few years later because of the difficulties in recovering sapphires in their bedrock. In North America , sapphires have been mined mostly from deposits in Montana : facies along the Missouri River near Helena, Montana , Dry Cottonwood Creek near Deer Lodge, Montana , and Rock Creek near Philipsburg, Montana . Fine blue Yogo sapphires are found at Yogo Gulch west of Lewistown, Montana . A few gem-grade sapphires and rubies have also been found in

14762-672: Was the case of the "Life and Pride of America Star Sapphire". Circa 1985, Roy Whetstine claimed to have bought the 1905-ct stone for $ 10 at the Tucson gem show, but a reporter discovered that L.A. Ward of Fallbrook, California, who appraised it at the price of $ 1200/ct, had appraised another stone of the exact same weight several years before Whetstine claimed to have found it. Bangkok-based Lotus Gemology maintains an updated listing of world auction records of ruby, sapphire, and spinel . As of November 2019, no sapphire has ever sold at auction for more than $ 17,295,796. Rubies are corundum with

14884-424: Was used on interior walls and ceilings as well as exterior walls as the wall cavity and exterior cladding isolated the clay plaster from moisture penetration. Application of clay plaster in brick structures risked water penetration from failed mortar joints on the exterior brick walls. In Economy Village, the rear and middle wythes of brick dwelling walls are laid in a clay and sand mortar with the front wythe bedded in

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