Misplaced Pages

#745254

92-430: Ruby is a pinkish red to blood-red colored gemstone , a variety of the mineral corundum ( aluminium oxide ). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapphires . Ruby is one of the traditional cardinal gems , alongside amethyst , sapphire , emerald , and diamond . The word ruby comes from ruber , Latin for red. The color of

184-513: A diamond -like appearance. The near-colorless diamond substitute is sold as "Titania", which is the old-fashioned chemical name for this oxide. However, rutile is seldom used in jewellery because it is not very hard (scratch-resistant), measuring only about 6 on the Mohs hardness scale . As the result of growing research interest in the photocatalytic activity of titanium dioxide, in both anatase and rutile phases (as well as biphasic mixtures of

276-789: 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

368-456: A coordination number of 3, resulting in a trigonal planar coordination. Rutile also shows a screw axis when its octahedra are viewed sequentially. When formed under reducing conditions, oxygen vacancies can occur, coupled to Ti centers. Hydrogen can enter these gaps, existing as an individual vacancy occupant (pairing as a hydrogen ion) or creating a hydroxide group with an adjacent oxygen. Rutile crystals are most commonly observed to exhibit

460-442: 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

552-504: 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

644-491: A downward pressure on ruby prices. Improvements used include color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them. The most common treatment is the application of heat. Most rubies at the lower end of the market are heat treated to improve color, remove purple tinge , blue patches, and silk. These heat treatments typically occur around temperatures of 1800 °C (3300 °F). Some rubies undergo

736-447: 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

828-459: A large premium over other rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Ruby is the traditional birthstone for July and is usually pinker than garnet , although some rhodolite garnets have a similar pinkish hue to most rubies. The world's most valuable ruby to be sold at auction

920-544: A little chromium at red heat . In 1903, Verneuil announced he could produce synthetic rubies on a commercial scale using this flame fusion process, later also known as the Verneuil process . By 1910, Verneuil's laboratory had expanded into a 30 furnace production facility, with annual gemstone production having reached 1,000 kilograms (2,000 lb) in 1907. Other processes in which synthetic rubies can be produced are through Czochralski's pulling process , flux process, and

1012-433: 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

SECTION 10

#1732772679746

1104-487: 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

1196-549: A prismatic or acicular growth habit with preferential orientation along their c axis, the [001] direction . This growth habit is favored as the {110} facets of rutile exhibit the lowest surface free energy and are therefore thermodynamically most stable. The c -axis oriented growth of rutile appears clearly in nanorods , nanowires and abnormal grain growth phenomena of this phase. In large enough quantities in beach sands, rutile forms an important constituent of heavy minerals and ore deposits . Miners extract and separate

1288-413: A process of low tube heat, when the stone is heated over charcoal of a temperature of about 1300 °C (2400 °F) for 20 to 30 minutes. The silk is partially broken, and the color is improved. Another treatment, which has become more frequent in recent years, is lead glass filling. Filling the fractures inside the ruby with lead glass (or a similar material) dramatically improves the transparency of

1380-626: 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

1472-599: A ruby is due to the element chromium . Some gemstones that are popularly or historically called rubies, such as the Black Prince's Ruby in the British Imperial State Crown , are actually spinels . These were once known as "Balas rubies". The quality of a ruby is determined by its color, cut, and clarity, which, along with carat weight, affect its value. The brightest and most valuable shade of red, called blood-red or pigeon blood, commands

1564-626: 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

1656-448: 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

1748-434: 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

1840-509: 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

1932-522: 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

SECTION 20

#1732772679746

2024-438: Is also found in placer deposits sourced from primary rutile. The occurrence of large specimen crystals is most common in pegmatites , skarns , and granite greisens . Rutile is found as an accessory mineral in some altered igneous rocks , and in certain gneisses and schists . In groups of acicular crystals it is frequently seen penetrating quartz as in the fléches d'amour from Graubünden , Switzerland . In 2005

2116-440: 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

2208-515: 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

2300-501: 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

2392-563: 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

2484-709: Is heated (for repairs) it should not be coated with boracic acid or any other substance, as this can etch the surface; it does not have to be "protected" like a diamond. The treatment can be identified by noting bubbles in cavities and fractures using a 10× loupe. In 1837, Gaudin made the first synthetic rubies by fusing potash alum at a high temperature with a little chromium as a pigment. In 1847, Ebelmen made white sapphire by fusing alumina in boric acid. In 1877, Edmond Frémy and industrial glass-maker Charles Feil made crystal corundum from which small stones could be cut. In 1887, Fremy and Auguste Verneuil manufactured artificial ruby by fusing BaF 2 and Al 2 O 3 with

2576-419: 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

2668-410: 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

2760-530: Is the Sunrise Ruby , which sold for US$ 34.8 million. Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness . Among the natural gems, only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissanite falling somewhere in between corundum (ruby) and diamond in hardness. Sapphire, ruby, and pure corundum are α-alumina, the most stable form of Al 2 O 3 , in which 3 electrons leave each aluminium ion to join

2852-438: Is the most important factor. Color divides into three components: hue , saturation and tone . Hue refers to color as we normally use the term. Transparent gemstones occur in the pure spectral hues of red, orange, yellow, green, blue, violet. In nature, there are rarely pure hues, so when speaking of the hue of a gemstone, we speak of primary and secondary and sometimes tertiary hues. Ruby is defined to be red. All other hues of

Ruby - Misplaced Pages Continue

2944-438: Is the most stable polymorph of TiO 2 at all temperatures, exhibiting lower total free energy than metastable phases of anatase or brookite. Consequently, the transformation of the metastable TiO 2 polymorphs to rutile is irreversible. As it has the lowest molecular volume of the three main polymorphs, it is generally the primary titanium-bearing phase in most high-pressure metamorphic rocks, chiefly eclogites . Within

3036-483: Is the only country in mainland Europe to have naturally occurring rubies. They can mainly be found around the city of Prilep . Macedonian rubies have a unique raspberry color. A few rubies have been found in the U.S. states of Montana , North Carolina , South Carolina and Wyoming . Spinel , another red gemstone, is sometimes found along with rubies in the same gem gravel or marble. Red spinels may be mistaken for rubies by those lacking experience with gems. However,

3128-566: Is used in watches, clocks, and oscillators. Rutile Rutile has one of the highest refractive indices at visible wavelengths of any known crystal and also exhibits a particularly large birefringence and high dispersion . Owing to these properties, it is useful for the manufacture of certain optical elements, especially polarization optics, for longer visible and infrared wavelengths up to about 4.5 micrometres. Natural rutile may contain up to 10% iron and significant amounts of niobium and tantalum . Rutile derives its name from

3220-541: Is widely used as a welding electrode covering . It is also used as a part of the ZTR index , which classifies highly weathered sediments. Rutile, as a large band-gap semiconductor , has in recent decades been the subject of significant research towards applications as a functional oxide for applications in photocatalysis and dilute magnetism . Research efforts typically utilize small quantities of synthetic rutile rather than mineral-deposit derived materials. Synthetic rutile

3312-446: 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

3404-760: The hydrothermal process . Most synthetic rubies originate from flame fusion, due to the low costs involved. Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curved striae and gas bubbles. The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i.e., a perfect ruby), in which case it will be suspected of being artificial. Dopants are added to some manufactured rubies so they can be identified as synthetic, but most need gemological testing to determine their origin. Synthetic rubies have technological uses as well as gemological ones. Rods of synthetic ruby are used to make ruby lasers and masers . The first working laser

3496-473: The 17th century techniques were developed to color foil red—by burning scarlet wool in the bottom part of the furnace—which was then placed under the imitation stone. Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers. Such terms are therefore discouraged from use by many gemological associations such as the Laboratory Manual Harmonisation Committee (LMHC). Gemstone A gemstone (also called

3588-415: 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

3680-534: The Aappaluttoq mine in Greenland began running. The rubies in Greenland are said to be among the oldest in the world at approximately 3 billion years old. The Aappaluttoq mine in Greenland is located 160 kilometers south of Nuuk, the capital of Greenland. The rubies are traceable from mine to market. The Montepuez ruby mine in northeastern Mozambique is situated on one of the most significant ruby deposits in

3772-512: The Al 2 O 3 crystal. However, the Cr ions are larger and have electron orbitals in different directions than aluminium. The octahedral arrangement of the O ions is distorted, and the energy levels of the different orbitals of those Cr ions are slightly altered because of the directions to the O ions. Those energy differences correspond to absorption in the ultraviolet, violet, and yellow-green regions of

Ruby - Misplaced Pages Continue

3864-936: The International Colored Gemstone Association (ICGA) have adopted the broader definition for ruby which encompasses its lighter shades, including pink. Historically, rubies have been mined in Thailand, in the Pailin and Samlout District of Cambodia , as well as in Afghanistan , Australia , Brazil , Colombia , India , Namibia , Japan , and Scotland. After the Second World War , ruby deposits were found in Madagascar , Mozambique , Nepal, Pakistan, Tajikistan , Tanzania , and Vietnam . The Republic of North Macedonia

3956-566: The Latin rutilus ('red'), in reference to the deep red color observed in some specimens when viewed by transmitted light. Rutile was first described in 1803 by Abraham Gottlob Werner using specimens obtained in Horcajuelo de la Sierra, Madrid (Spain), which is consequently the type locality . Rutile is a common accessory mineral in high-temperature and high-pressure metamorphic rocks and in igneous rocks . Thermodynamically , rutile

4048-532: The Republic of Sierra Leone in West Africa had a production capacity of 23% of the world's annual rutile supply, which rose to approximately 30% in 2008. Rutile has a tetragonal unit cell , with unit cell parameters a = b = 4.584 Å, and c = 2.953 Å. The titanium cations have a coordination number of 6, meaning they are surrounded by an octahedron of 6 oxygen atoms. The oxygen anions have

4140-502: The United States, a minimum color saturation must be met to be called a ruby; otherwise, the stone will be called a pink sapphire . Drawing a distinction between rubies and pink sapphires is relatively new, having arisen sometime in the 20th century. Often, the distinction between ruby and pink sapphire is not clear and can be debated. As a result of the difficulty and subjectiveness of such distinctions, trade organizations such as

4232-529: 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

4324-455: 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

4416-475: 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

4508-673: 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

4600-444: 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

4692-598: The crystal during that time, they can stimulate more fluorescent photons to be emitted in-phase with them, thus strengthening the intensity of that red light. By arranging mirrors or other means to pass emitted light repeatedly through the crystal, a ruby laser in this way produces a very high intensity of coherent red light. All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, simulants, or substitutes. Usually,

SECTION 50

#1732772679746

4784-457: The crystal growth process) to be ten to twenty times less than in the natural gemstones. Theodore Maiman says that "because of the low chromium level in these crystals they display a lighter red color than gemstone ruby and are referred to as pink ruby ." After absorbing short-wavelength light, there is a short interval of time when the crystal lattice of ruby is in an excited state before fluorescence occurs. If 694-nanometer photons pass through

4876-572: 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

4968-410: 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

5060-410: 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

5152-445: 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

5244-439: 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

5336-451: 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

5428-478: The finest red spinels, now heavily sought, can have values approaching all but the finest examples of ruby. The Mogok Valley in Upper Myanmar (Burma) was for centuries the world's main source for rubies. That region has produced some exceptional rubies; however, in recent years few good rubies have been found. In central Myanmar, the area of Mong Hsu began producing rubies during the 1990s and rapidly became

5520-417: 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

5612-494: The gem species corundum are called sapphire. Ruby may exhibit a range of secondary hues, including orange, purple, violet, and pink. Because rubies host many inclusions, their clarity is evaluated by the inclusions’ size, number, location, and visibility. Rubies with the highest clarity grades are known as “eye-clean,” because their inclusions are the least visible to the naked human eye. Rubies may also have thin, intersecting inclusions called silk. Silk can scatter light, brightening

SECTION 60

#1732772679746

5704-443: The gem's appearance, and the presence of silk can also show whether a ruby has been previously heat treated, since intense heat will degrade a ruby's silk. Improving the quality of gemstones by treating them is common practice. Some treatments are used in almost all cases and are therefore considered acceptable. During the late 1990s, a large supply of low-cost materials caused a sudden surge in supply of heat-treated rubies, leading to

5796-668: 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

5888-425: 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

5980-402: The igneous environment, rutile is a common accessory mineral in plutonic igneous rocks , though it is also found occasionally in extrusive igneous rocks , particularly those such as kimberlites and lamproites that have deep mantle sources. Anatase and brookite are found in the igneous environment, particularly as products of autogenic alteration during the cooling of plutonic rocks; anatase

6072-419: 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

6164-435: 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

6256-516: 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

6348-538: 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

6440-689: 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

6532-804: 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

6624-450: 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

6716-507: 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

6808-410: The regular octahedral group of six nearby O ions; in pure corundum this leaves all of the aluminium ions with a very stable configuration of no unpaired electrons or unfilled energy levels, and the crystal is perfectly colorless, and transparent except for flaws. When a chromium atom replaces an occasional aluminium atom, it too loses 3 electrons to become a chromium ion to maintain the charge balance of

6900-415: The rough stone is heated before cutting. These days, almost all rubies are treated in some form, with heat treatment being the most common practice. Untreated rubies of high quality command a large premium. Some rubies show a three-point or six-point asterism or "star". These rubies are cut into cabochons to display the effect properly. Asterisms are best visible with a single-light source and move across

6992-531: 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

7084-426: 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

7176-492: 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

7268-732: The single greatest use of titanium worldwide. Nanoscale particles of rutile are transparent to visible light but are highly effective in the absorption of ultraviolet radiation ( sunscreen ). The UV absorption of nano-sized rutile particles is blue-shifted compared to bulk rutile so that higher-energy UV light is absorbed by the nanoparticles. Hence, they are used in sunscreens to protect against UV-induced skin damage. Small rutile needles present in gems are responsible for an optical phenomenon known as asterism . Asteriated gems are known as "star" gems. Star sapphires , star rubies , and other star gems are highly sought after and are generally more valuable than their normal counterparts. Rutile

7360-401: The spectrum. If one percent of the aluminium ions are replaced by chromium in ruby, the yellow-green absorption results in a red color for the gem. Additionally, absorption at any of the above wavelengths stimulates fluorescent emission of 694-nanometer-wavelength red light, which adds to its red color and perceived luster . The chromium concentration in artificial rubies can be adjusted (in

7452-489: The stone as the light moves or the stone is rotated. Such effects occur when light is reflected off the "silk" (the structurally oriented rutile needle inclusions) in a certain way. This is one example where inclusions increase the value of a gemstone. Furthermore, rubies can show color changes—though this occurs very rarely—as well as chatoyancy or the "cat's eye" effect. Generally, gemstone-quality corundum in all shades of red, including pink, are called rubies. However, in

7544-404: 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

7636-406: The stone, making previously unsuitable rubies fit for applications in jewelry. The process is done in four steps: If a color needs to be added, the glass powder can be "enhanced" with copper or other metal oxides as well as elements such as sodium, calcium, potassium etc. The second heating process can be repeated three to four times, even applying different mixtures. When jewelry containing rubies

7728-524: 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

7820-432: The two phases), rutile TiO 2 in powder and thin film form is frequently fabricated in laboratory conditions through solution based routes using inorganic precursors (typically TiCl 4 ) or organometallic precursors (typically alkoxides such as titanium isopropoxide , also known as TTIP). Depending on synthesis conditions, the first phase to crystallize may be the metastable anatase phase, which can then be converted to

7912-419: 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

8004-399: The valuable minerals – e.g., rutile, zircon , and ilmenite . The main uses for rutile are the manufacture of refractory ceramic , as a pigment , and for the production of titanium metal . Finely powdered rutile is a brilliant white pigment and is used in paints , plastics , paper , foods, and other applications that call for a bright white color. Titanium dioxide pigment is

8096-516: The world's main ruby mining area. The most recently found ruby deposit in Myanmar is in Namya (Namyazeik) located in the northern state of Kachin . In Pakistani Kashmir there are vast proven reserves of millions of rubies, worth up to half a billion dollars. However, as of 2017 there was only one mine (at Chitta Katha) due to lack of investment. In Afghanistan , rubies are mined at Jegdalek. In 2017

8188-426: The world, although, rubies were only discovered here for the first time in 2009. In less than a decade, Mozambique has become the world's most productive source for gem-quality ruby. Rubies, as with other gemstones, are graded using criteria known as the four Cs, namely color, cut, clarity and carat weight. Rubies are also evaluated on the basis of their geographic origin. In the evaluation of colored gemstones, color

8280-461: 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

8372-462: Was first produced in 1948 and is sold under a variety of names. It can be produced from the titanium ore ilmenite through the Becher process . Very pure synthetic rutile is transparent and almost colorless, being slightly yellow, in large pieces. Synthetic rutile can be made in a variety of colors by doping. The high refractive index gives an adamantine luster and strong refraction that leads to

8464-561: Was made by Theodore H. Maiman in 1960. Maiman used a solid-state light-pumped synthetic ruby to produce red laser light at a wavelength of 694 nanometers (nm). Ruby lasers are still in use. Rubies are also used in applications where high hardness is required such as at wear-exposed locations in mechanical clockworks, or as scanning probe tips in a coordinate measuring machine . Imitation rubies are also marketed. Red spinels , red garnets , and colored glass have been falsely claimed to be rubies. Imitations go back to Roman times and already in

#745254