103-534: Sapphire 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
206-467: 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
309-442: A cubic crystal system, are often found as octahedrons . Gemstones are classified into different groups , species , and varieties . For example, ruby is the red variety of the species corundum , while any other color of corundum is considered sapphire. Other examples are the emerald (green), aquamarine (blue), red beryl (red), goshenite (colorless), heliodor (yellow), and morganite (pink), which are all varieties of
412-504: A diamond. With modification, these categories can be useful in understanding the grading of all gemstones. The four criteria carry different weights depending upon whether they are applied to colored gemstones or to colorless diamonds. In diamonds, the cut is the primary determinant of value, followed by clarity and color. An ideally cut diamond will sparkle, to break down light into its constituent rainbow colors (dispersion), chop it up into bright little pieces (scintillation), and deliver it to
515-469: 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 the transfer of an electron from one transition-metal ion to another via
618-447: A gemstone is a natural stone or synthetic, the chemical, physical, and optical characteristics are the same: They are composed of the same mineral and are colored by the same trace materials, have the same hardness and density and strength , and show the same color spectrum , refractive index , and birefringence (if any). Lab-created stones tend to have a more vivid color since impurities common in natural stones are not present in
721-408: 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
824-433: A more desirable blue / purple color. A considerable portion of all sapphire and ruby is treated with a variety of heat treatments to improve both color and clarity. When jewelry containing diamonds is heated for repairs, the diamond should be protected with boric acid ; otherwise, the diamond, which is pure carbon, could be burned on the surface or even burned completely up. When jewelry containing sapphires or rubies
927-487: A number of inclusions), cut, unusual optical phenomena within the stone such as color zoning (the uneven distribution of coloring within a gem) and asteria (star effects). Apart from the more generic and commonly used gemstones such as from diamonds , rubies , sapphires , and emeralds , pearls and opal have also been defined as precious in the jewellery trade. Up to the discoveries of bulk amethyst in Brazil in
1030-443: 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, the world's production of synthetic sapphire
1133-500: 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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#17327730726611236-626: A result of this is the exploitation of natural resources and labor within gemstone mining operations. Many mines, particularly in developing countries, face challenges such as inadequate safety measures, low wages, and poor working conditions. Miners , often from disadvantaged backgrounds, endure hazardous working conditions and receive meager wages, contributing to cycles of poverty and exploitation. Gemstone mining operations are frequently conducted in remote or underdeveloped areas, lacking proper infrastructure and access to essential services such as healthcare and education. This further contributes to
1339-626: A stone is untreated, while another lab might conclude that it is heat-treated. To minimize such differences, seven of the most respected labs, AGTA-GTL (New York), CISGEM (Milano), GAAJ-ZENHOKYO (Tokyo), GIA (Carlsbad), GIT (Bangkok), Gübelin (Lucerne) and SSEF (Basel), have established the Laboratory Manual Harmonisation Committee (LMHC), for the standardization of wording reports, promotion of certain analytical methods and interpretation of results. Country of origin has sometimes been difficult to determine, due to
1442-448: Is hardstone . Use of the terms 'precious' and 'semi-precious' in a commercial context is, arguably, misleading in that it suggests certain stones are more valuable than others when this is not reflected in the actual market value, although it would generally be correct if referring to desirability. In modern times gemstones are identified by gemologists , who describe gems and their characteristics using technical terminology specific to
1545-434: Is a common practice. Most citrine is made by heating amethyst , and partial heating with a strong gradient results in " ametrine " – a stone partly amethyst and partly citrine. Aquamarine is often heated to remove yellow tones, or to change green colors into the more desirable blue, or enhance its existing blue color to a deeper blue. Nearly all tanzanite is heated at low temperatures to remove brown undertones and give
1648-509: Is a recognized grading of the gem's luster, transparency, or "brilliance". Very transparent gems are considered " first water ", while "second" or "third water" gems are those of a lesser transparency. Additionally, material or flaws within a stone may be present as inclusions . Gemstones have no universally accepted grading system. Diamonds are graded using a system developed by the Gemological Institute of America (GIA) in
1751-485: 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
1854-462: 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 a variety of shades. Corundum that contains extremely low levels of chromophores
1957-439: 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
2060-522: Is also colored to make the emerald appear of better color as well as clarity. Turquoise is also commonly treated in a similar manner. Fracture filling has been in use with different gemstones such as diamonds, emeralds, and sapphires. In 2006 "glass-filled rubies" received publicity. Rubies over 10 carats (2 g) with large fractures were filled with lead glass, thus dramatically improving the appearance (of larger rubies in particular). Such treatments are fairly easy to detect. Another treatment method that
2163-492: 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
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#17327730726612266-451: 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
2369-426: 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
2472-440: Is commonly used to treat gemstones is bleaching. This method uses a chemical in order to reduce the colour of the gem. After bleaching, a combination treatment can be done by dying the gemstone once the unwanted colours are removed. Hydrogen peroxide is the most commonly used product used to alter gemstones and have notably been used to treat jade and pearls. The treatment of bleaching can also be followed by impregnation, which allows
2575-515: Is considered to be one of the important gemstones after rubies, emeralds, and sapphires according to Gübelin Gemlab. Even though it is a tourmaline, Paraiba Tourmaline is one of the most expensive gemstones. There are a number of laboratories which grade and provide reports on gemstones. Each laboratory has its own methodology to evaluate gemstones. A stone can be called "pink" by one lab while another lab calls it "padparadscha". One lab can conclude
2678-407: 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
2781-501: Is emerald (green). Yellow, red and blue beryls are possible but much more rare. Synthetic emerald became possible with the development of the flux growth process and is produced in this way and well as hydrothermal growth. Types of synthetic quartz include citrine, rose quartz, and amethyst. Natural occurring quartz is not rare, but is nevertheless synthetically produced as it has practical application outside of aesthetic purposes. Quartz generates an electric current when under pressure and
2884-563: Is essential. Additionally, investing in community development projects, such as education and healthcare initiatives, can help alleviate poverty and empower marginalized communities dependent on the gemstone industry. Collaboration across sectors is crucial for fostering a more equitable and sustainable gemstone trade that benefits both producers and consumers while respecting human rights and environmental integrity. Synthetic gemstones are distinct from imitation or simulated gems. Synthetic gems are physically, optically, and chemically identical to
2987-419: Is heated, those stones should not be coated with boric acid (which can etch the surface) or any other substance. They do not have to be protected from burning, like a diamond (although the stones do need to be protected from heat stress fracture by immersing the part of the jewelry with stones in the water when metal parts are heated). The irradiation process is widely practiced in jewelry industry and enabled
3090-556: 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,
3193-431: 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
Sapphire - Misplaced Pages Continue
3296-485: 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 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
3399-410: Is perceived by the viewer as sparkle. There are many commonly used shapes for faceted stones . The facets must be cut at the proper angles, which varies depending on the optical properties of the gem. If the angles are too steep or too shallow, the light will pass through and not be reflected back toward the viewer. The faceting machine is used to hold the stone onto a flat lap for cutting and polishing
3502-415: 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
3605-403: 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
3708-709: 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
3811-536: 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
3914-482: Is used in watches, clocks, and oscillators. Cut (gems) A gemstone desired to be used in jewelry is cut depending on the size and shape of the rough stone, as well as the desired piece of jewelry to be made. As a general rule, a cut gemstone will reduce the mass (in carats ) by about 50%. Among the several techniques used to work with gemstones are sawing, grinding, sanding , lapping, polishing , grilling, and tumbling . The diamond cut planning stage
4017-631: 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
4120-446: The ancient Greeks , begins with a distinction between precious and semi-precious ; similar distinctions are made in other cultures. In modern use, the precious stones are emerald , ruby , sapphire and diamond , with all other gemstones being semi-precious. This distinction reflects the rarity of the respective stones in ancient times, as well as their quality: all are translucent , with fine color in their purest forms (except for
4223-566: 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
Sapphire - Misplaced Pages Continue
4326-408: 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 is a specific change in energy for the electron, and electromagnetic energy
4429-661: 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
4532-415: The 19th century, amethyst was considered a "precious stone" as well, going back to ancient Greece. Even in the last century certain stones such as aquamarine , peridot and cat's eye ( cymophane ) have been popular and hence been regarded as precious, thus reinforcing the notion that a mineral's rarity may have been implicated in its classification as a precious stone and thus contribute to its value. Today
4635-522: 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
4738-694: 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
4841-529: The basis of their alleged healing powers. A gemstone that has been rising in popularity is Cuprian Elbaite Tourmaline which is also called "Paraiba Tourmaline". It was first discovered in the late 1980s in Paraíba, Brazil and later in Mozambique and Nigeria. It is famous for its glowing neon blue color. Paraiba Tourmaline has become one of the most popular gemstones in recent times thanks to its color and
4944-589: 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
5047-414: 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
5150-464: 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
5253-430: 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
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#17327730726615356-459: 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
5459-455: The color from white to blue. Most green quartz (Oro Verde) are also irradiated to achieve the yellow-green color. Diamonds are mainly irradiated to become blue-green or green, although other colors are possible. When light-to-medium-yellow diamonds are treated with gamma rays they may become green; with a high-energy electron beam, blue. Emeralds containing natural fissures are sometimes filled with wax or oil to disguise them. This wax or oil
5562-408: 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
5665-525: The colorless diamond), and very hard with a hardness score of 8 to 10 on the Mohs scale . Other stones are classified by their color, translucency , and hardness. The traditional distinction does not necessarily reflect modern values; for example, while garnets are relatively inexpensive, a green garnet called tsavorite can be far more valuable than a mid-quality emerald. Another traditional term for semi-precious gemstones used in art history and archaeology
5768-673: The constant discovery of new source locations. Determining a "country of origin" is thus much more difficult than determining other aspects of a gem (such as cut, clarity, etc.). Gem dealers are aware of the differences between gem laboratories and will make use of the discrepancies to obtain the best possible certificate. A few gemstones are used as gems in the crystal or other forms in which they are found. Most, however, are cut and polished for usage as jewelry. The two main classifications are as follows: Stones which are opaque or semi-opaque such as opal , turquoise , variscite , etc. are commonly cut as cabochons. These gems are designed to show
5871-444: The creation of gemstone colors that do not exist or are extremely rare in nature. However, particularly when done in a nuclear reactor , the processes can make gemstones radioactive. Health risks related to the residual radioactivity of the treated gemstones have led to government regulations in many countries. Virtually all blue topaz , both the lighter and the darker blue shades such as "London" blue, has been irradiated to change
5974-469: 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
6077-709: 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 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)
6180-687: 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,
6283-444: 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
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#17327730726616386-572: The earliest methods of gemstone treatment date back to the Minoan Age, for example foiling, which is where metal foil is used to enhance a gemstone's colour. Other methods recorded 2000 years ago in the book Natural History by Pliny the Elder include oiling and dyeing/staining. Heat can either improve or spoil gemstone color or clarity. The heating process has been well known to gem miners and cutters for centuries, and in many stone types heating
6489-410: The early 1950s. Historically, all gemstones were graded using the naked eye. The GIA system included a major innovation: the introduction of 10x magnification as the standard for grading clarity. Other gemstones are still graded using the naked eye (assuming 20/20 vision). A mnemonic device , the "four Cs" (color, cut, clarity, and carats), has been introduced to help describe the factors used to grade
6592-410: The eye (brilliance). In its rough crystalline form, a diamond will do none of these things; it requires proper fashioning and this is called "cut". In gemstones that have color, including colored diamonds, the purity, and beauty of that color is the primary determinant of quality. Physical characteristics that make a colored stone valuable are color, clarity to a lesser extent (emeralds will always have
6695-445: The eye as the perceived color. A ruby appears red because it absorbs all other colors of white light while reflecting red. A material which is mostly the same can exhibit different colors. For example, ruby and sapphire have the same primary chemical composition (both are corundum ) but exhibit different colors because of impurities which absorb and reflect different wavelengths of light depending on their individual compositions. Even
6798-439: The fact that these impurities can be "manipulated", thus changing the color of the gem. Gemstones are often treated to enhance the color or clarity of the stone. In some cases, the treatment applied to the gemstone can also increase its durability. Even though natural gemstones can be transformed using the traditional method of cutting and polishing, other treatment options allow the stone's appearance to be enhanced. Depending on
6901-451: The field of gemology . The first characteristic a gemologist uses to identify a gemstone is its chemical composition . For example, diamonds are made of carbon ( C ) and rubies of aluminium oxide ( Al 2 O 3 ). Many gems are crystals which are classified by their crystal system such as cubic or trigonal or monoclinic . Another term used is habit , the form the gem is usually found in. For example, diamonds, which have
7004-417: The flat facets. Rarely, some cutters use special curved laps to cut and polish curved facets. The color of any material is due to the nature of light itself. Daylight, often called white light, is all of the colors of the spectrum combined. When light strikes a material, most of the light is absorbed while a smaller amount of a particular frequency or wavelength is reflected. The part that is reflected reaches
7107-541: 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
7210-854: 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 ,
7313-668: The gemstone trade no longer makes such a distinction. Many gemstones are used in even the most expensive jewelry, depending on the brand-name of the designer, fashion trends, market supply, treatments, etc. Nevertheless, diamonds, rubies, sapphires, and emeralds still have a reputation that exceeds those of other gemstones. Rare or unusual gemstones, generally understood to include those gemstones which occur so infrequently in gem quality that they are scarcely known except to connoisseurs, include andalusite , axinite , cassiterite , clinohumite , painite and red beryl . Gemstone pricing and value are governed by factors and characteristics in
7416-425: The gemstone's durability to be increased. The socio-economic dynamics of the gemstone industry are shaped by market forces and consumer preferences and typically go undiscussed. Changes in demand and prices can significantly affect the livelihoods of those involved in gemstone mining and trade, particularly in developing countries where the industry serves as a crucial source of income. A situation that arises as
7519-435: 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
7622-663: 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
7725-410: 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
7828-419: The look and color of the real stone but possess neither their chemical nor physical characteristics. In general, all are less hard than diamond. Moissanite actually has a higher refractive index than diamond, and when presented beside an equivalently sized and cut diamond will show more "fire". Cultured, synthetic, or "lab-created" gemstones are not imitations: The bulk mineral and trace coloring elements are
7931-435: The mineral species beryl . Gems are characterized in terms of their color (hue, tone and saturation), optical phenomena, luster, refractive index , birefringence , dispersion , specific gravity , hardness , cleavage , and fracture . They may exhibit pleochroism or double refraction . They may have luminescence and a distinctive absorption spectrum . Gemstones may also be classified in terms of their "water". This
8034-516: The most common on the market currently. Synthetic corundum includes ruby (red variation) and sapphire (other color variations), both of which are considered highly desired and valued. Ruby was the first gemstone to be synthesized by Auguste Verneuil with his development of the flame-fusion process in 1902. Synthetic corundum continues to be made typically by flame-fusion as it is most cost-effective, but can also be produced through flux growth and hydrothermal growth. The most common synthesized beryl
8137-402: 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
8240-538: The natural stone, but are created in a laboratory. Imitation or simulated stones are chemically different from the natural stone, but may appear quite similar to it; they can be more easily manufactured synthetic gemstones of a different mineral ( spinel ), glass, plastic, resins, or other compounds. Examples of simulated or imitation stones include cubic zirconia , composed of zirconium oxide, synthetic moissanite , and uncolored, synthetic corundum or spinels ; all of which are diamond simulants . The simulants imitate
8343-689: The pre-existing socio-economic disparities and obstructs community development such that the benefits of gemstone extraction may not adequately reach those directly involved in the process. Another such issue revolves around environmental degradation resulting from mining activities. Environmental degradation can pose long-term threats to ecosystems and biodiversity, further worsening the socio-economic state in affected regions. Unregulated mining practices often result in deforestation , soil erosion , and water contamination thus threatening ecosystems and biodiversity . Unregulated mining activity can also cause depletion of natural resources, thus diminishing
8446-804: The prevalence of illicit practices undermine market integrity and trust. The lack of transparency and accountability in the supply chain aggravates pre-existing inequalities, as middlemen and corporations often capture a disproportionate share of the profits. As a result, the unequal distribution of profits along the supply chain does little to improve socio-economic inequalities, particularly in regions where gemstones are mined. Addressing these socio-economic challenges requires intensive effort from various stakeholders, including governments, industry executives, and society, to promote sustainable practices and ensure equitable outcomes for all involved parties. Implementing and enforcing regulations to ensure fair labor practices, environmental sustainability, and ethical sourcing
8549-450: The prospects for sustainable development . The environmental impact of gemstone mining not only poses a threat to ecosystems but also undermines the long-term viability of the industry by diminishing the quality and quantity of available resources. Furthermore, the gemstone industry is also susceptible to issues related to transparency and ethics, which impact both producers and consumers. The lack of standardized certification processes and
8652-507: The quality of the stone. These characteristics include clarity, rarity, freedom from defects, the beauty of the stone, as well as the demand for such stones. There are different pricing influencers for both colored gemstones, and for diamonds. The pricing on colored stones is determined by market supply-and-demand, but diamonds are more intricate. In the addition to the aesthetic and adorning/ornamental purpose of gemstones, there are many proponents of energy medicine who also value gemstones on
8755-646: 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;
8858-519: 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
8961-539: 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
9064-461: 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
9167-531: The same in both. For example, diamonds , rubies , sapphires , and emeralds have been manufactured in labs that possess chemical and physical characteristics identical to the naturally occurring variety. Synthetic (lab created) corundum , including ruby and sapphire, is very common and costs much less than the natural stones. Small synthetic diamonds have been manufactured in large quantities as industrial abrasives , although larger gem-quality synthetic diamonds are becoming available in multiple carats. Whether
9270-426: The same named gemstone can occur in many different colors: sapphires show different shades of blue and pink and "fancy sapphires" exhibit a whole range of other colors from yellow to orange-pink, the latter called " padparadscha sapphire ". This difference in color is based on the atomic structure of the stone. Although the different stones formally have the same chemical composition and structure, they are not exactly
9373-492: The same. Every now and then an atom is replaced by a completely different atom, sometimes as few as one in a million atoms. These so-called impurities are sufficient to absorb certain colors and leave the other colors unaffected. For example, beryl , which is colorless in its pure mineral form, becomes emerald with chromium impurities. If manganese is added instead of chromium , beryl becomes pink morganite . With iron, it becomes aquamarine. Some gemstone treatments make use of
9476-404: The stone's color, luster and other surface properties as opposed to internal reflection properties like brilliance. Grinding wheels and polishing agents are used to grind, shape, and polish the smooth dome shape of the stones. Gems that are transparent are normally faceted, a method that shows the optical properties of the stone's interior to its best advantage by maximizing reflected light which
9579-524: The synthetic stone. Synthetics are made free of common naturally occurring impurities that reduce gem clarity or color unless intentionally added in order to provide a more drab, natural appearance, or to deceive an assayer. On the other hand, synthetics often show flaws not seen in natural stones, such as minute particles of corroded metal from lab trays used during synthesis. Some gemstones are more difficult to synthesize than others and not all stones are commercially viable to attempt to synthesize. These are
9682-419: The type and extent of treatment, they can affect the value of the stone. Some treatments are used widely because the resulting gem is stable, while others are not accepted most commonly because the gem color is unstable and may revert to the original tone. Before the innovation of modern-day tools, thousands of years ago, people were recorded to use a variety of techniques to treat and enhance gemstones. Some of
9785-503: 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
9888-445: 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)
9991-461: The world, the industry of coloured gemstones (i.e. anything other than diamonds) is currently estimated at US$ 1.55 billion as of 2023 and is projected to steadily increase to a value of US$ 4.46 billion by 2033. A gem expert is a gemologist , a gem maker is called a lapidarist or gemcutter ; a diamond cutter is called a diamantaire . The traditional classification in the West, which goes back to
10094-416: 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,
10197-1010: Was 250 tons (1.25 × 10 carats), mostly by the United States and Russia. The availability of cheap synthetic sapphire unlocked many industrial uses for this unique material. Gemstone A gemstone (also called a fine gem , jewel , precious stone , semiprecious stone , or simply gem ) is a piece of mineral crystal which, when cut or polished, is used to make jewelry or other adornments . Certain rocks (such as lapis lazuli , opal , and obsidian ) and occasionally organic materials that are not minerals (such as amber , jet , and pearl ) may also be used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some softer minerals such as brazilianite may be used in jewelry because of their color or luster or other physical properties that have aesthetic value . However, generally speaking, soft minerals are not typically used as gemstones by virtue of their brittleness and lack of durability. Found all over
10300-487: 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
10403-547: 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,
10506-611: 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
10609-670: 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
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