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67-450: Topaz is a silicate mineral made of aluminum and fluorine with the chemical formula Al 2 Si O 4 ( F , OH ) 2 . It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden brown to yellow-orange. Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple. Topaz

134-413: A combination of amorphous Al 2 O 3 , Na 2 SiF 6 , and water which is heated to a temperature of 500 °C, put under a pressure of 4000 bars, and left for 9 days. To care for a topaz gemstone, it is best to avoid ultrasonic cleaners or steam as this could produce small fractures within the crystal. Warm water with soap is the best way to wash it. To choose an ethically sourced topaz gemstone, it

201-501: A cut and polished surface of the gem. Commonly encountered species and varieties of tourmaline include the following: The most common species of tourmaline is schorl , the sodium iron (divalent) endmember of the group. It may account for 95% or more of all tourmaline in nature. The early history of the mineral schorl shows that the name "schorl" was in use prior to 1400 because a village known today as Zschorlau (in Saxony , Germany)

268-554: A drag response when a neodymium magnet is applied. Any blue tourmaline that is diamagnetic can be identified as paraiba tourmaline colored by copper in contrast to magnetic blue tourmaline colored by iron. Some tourmaline gems, especially pink to red colored stones, are altered by heat treatment to improve their color. Overly dark red stones can be lightened by careful heat treatment. The pink color in manganese-containing near-colorless to pale pink stones can be greatly increased by irradiation with gamma-rays or electron beams. Irradiation

335-404: A fragment of kaolin . This in turn binds to three triangular borate ions. Units joined end to end form columns running the length of the crystal. Each column binds with two other columns offset one-third and two-thirds of the vertical length of a single unit to form bundles of three columns. Bundles are packed together to form the final crystal structure. Because the neighboring columns are offset,

402-480: A large component of mining operations, is drawn away from neighboring communities to create a lack of water. Tailings leftover from the mining process can leach contaminants into nearby water systems and can contaminate the drinking water of local communities. Some ways humans can be impacted by gem mining is through danger in mines and inadequate compensation. Accidents such as collapsing mines and machinery malfunctioning can put human life in danger. Those working in

469-417: A major constituent of deep ocean sediment , and of diatomaceous earth . A silicate mineral is generally an inorganic compound consisting of subunits with the formula [SiO 2+ n ] . Although depicted as such, the description of silicates as anions is a simplification. Balancing the charges of the silicate anions are metal cations, M . Typical cations are Mg , Fe , and Na . The Si-O-M linkage between

536-751: A more recent gem, weighed 22,892.5 carats (4,578.50 g). Large, vivid blue topaz specimens from the St. Anns mine in Zimbabwe were found in the late 1980s. Colorless and light-blue varieties of topaz are found in Precambrian granite in Mason County, Texas within the Llano Uplift . There is no commercial mining of topaz in that area. It is possible to synthesize topaz. Large-scale topaz mining typically uses open pit and underground mining to extract

603-455: A result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting , crystallization , fractionation , metamorphism , weathering , and diagenesis . Living organisms also contribute to this geologic cycle . For example, a type of plankton known as diatoms construct their exoskeletons ("frustules") from silica extracted from seawater . The frustules of dead diatoms are

670-594: A sample of topaz. After heating, the topaz lost mass, and through examination Brewster concluded Topaz was formed in a wet environment creating these liquid-filled cavities. This liquid is a hydrocarbon with a refractive index of 1·13. Topaz's crystal habit takes many forms. It can display a range of slender and long crystals to bulky and short. There can also be variation in the terminations displaying blunt, pyramidal, chisel, or wedge-shaped terminations. The perfect cleavage {001} in topaz breaks no Si-O bonds within its structure and only breaks Al-O and Al-F bonds. This cleavage

737-420: A shared oxygen vertex—a silicon:oxygen ratio of 2:7. The Nickel–Strunz classification is 09.B. Examples include: Cyclosilicates (from Greek κύκλος kýklos 'circle'), or ring silicates, have three or more tetrahedra linked in a ring. The general formula is (Si x O 3 x ) , where one or more silicon atoms can be replaced by other 4-coordinated atom(s). The silicon:oxygen ratio is 1:3. Double rings have

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804-523: A sparkling table facet surrounded by dead-looking crown facets or a ring of sparkling crown facets with a dull well-like table. It also takes an exceptionally fine polish, and can sometimes be distinguished from citrine by its slippery feel alone (quartz cannot be polished to this level of smoothness). Another method of distinguishing topaz from quartz is by placing the unset stone in a solution of bromoform or methylene iodide . Quartz will invariably float in these solutions, whereas topaz will sink. Topaz

871-424: A tendency to break along such a cleavage plane if struck with sufficient force. Topaz has a relatively low index of refraction for a gemstone, and so stones with large facets or tables do not sparkle as readily as stones cut from minerals with higher refractive indices, though quality colorless topaz sparkles and shows more "life" than similarly cut quartz. When given a typical "brilliant" cut, topaz may either show

938-457: A threat of landslides . The pollution produced by mining can impact the environment around it and damage its health. Deforestation undergone to create the mine, along with the machinery used during the mining process, adds greenhouse gasses to the atmosphere. Deforestation also removes habitats and biodiversity from a large area of natural space. These disruptions to the ecosystem can be challenging to wildlife and local populations. Water, also

1005-551: A three-dimensional framework of silicate tetrahedra with SiO 2 in a 1:2 ratio. This group comprises nearly 75% of the crust of the Earth . Tectosilicates, with the exception of the quartz group, are aluminosilicates . The Nickel–Strunz classifications are 09.F and 09.G, 04.DA (Quartz/ silica family). Examples include: Tourmaline The name is derived from the Sinhalese tōramalli ( ටෝරමල්ලි ), which refers to

1072-401: Is 09.D – examples include: Phyllosilicates (from Greek φύλλον phýllon 'leaf'), or sheet silicates, form parallel sheets of silicate tetrahedra with Si 2 O 5 or a 2:5 ratio. The Nickel–Strunz classification is 09.E. All phyllosilicate minerals are hydrated , with either water or hydroxyl groups attached. Examples include: Tectosilicates, or "framework silicates," have

1139-454: Is a nesosilicate mineral , and more specifically, an aluminosilicate mineral. It is one of the hardest naturally occurring minerals and has a relatively low index of refraction . It has the orthorhombic crystal system and a dipyramidial crystal class . It occurs in many places in the world. Some of the most popular places where topaz is sourced are Brazil and Russia. Topaz is often mined in open pit or alluvial settings. The word "topaz"

1206-776: Is a durable mineral and can be found in minor amounts as grains in sandstone and conglomerate , and is part of the ZTR index for highly weathered sediments. Gem and specimen tourmaline is mined chiefly in Brazil and many parts of Africa , including Tanzania , Nigeria , Kenya , Madagascar , Mozambique , Malawi , and Namibia . It is also mined in Asia , notably in Pakistan , Afghanistan , and Indonesia as well as in Sri Lanka and India , where some placer material suitable for gem use

1273-618: Is almost impossible to detect in tourmalines, and does not, currently, affect the value. Heavily included tourmalines, such as rubellite and Brazilian paraiba, are sometimes clarity-enhanced. A clarity-enhanced tourmaline (especially the paraiba variety) is worth much less than an untreated gem of equal clarity. Tourmaline is found in granite and granite pegmatites and in metamorphic rocks such as schist and marble . Schorl and lithium-rich tourmalines are usually found in granite and granite pegmatite. Magnesium-rich tourmalines, dravites, are generally restricted to schists and marble. Tourmaline

1340-466: Is colorless. Bi-colored and multicolored crystals are common, reflecting variations of fluid chemistry during crystallization. Crystals may be green at one end and pink at the other, or green on the outside and pink inside; this type is called watermelon tourmaline and is prized in jewelry. An excellent example of watermelon tourmaline jewelry is a brooch piece (1969, gold, watermelon tourmaline, diamonds) by Andrew Grima (British, b. Italy, 1921–2007), in

1407-530: Is commonly associated with silicic igneous rocks of the granite and rhyolite type. It typically crystallizes in granitic pegmatites or in vapor cavities in rhyolite lava flows including those at Topaz Mountain in western Utah and Chivinar in South America. It can be found with fluorite and cassiterite in various areas including the Ural and Ilmensky mountains of Russia, Afghanistan, Sri Lanka,

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1474-646: Is commonly used to date written as Na(Li 1.5 Al 1.5 )Al 6 (BO 3 ) 3 [Si 6 O 18 ](OH) 3 (OH) . The first crystal structure determination of a Li-rich tourmaline was published in 1972 by Donnay and Barton, performed on a pink elbaite from San Diego County , California , United States. The tourmaline mineral group is chemically one of the most complicated groups of silicate minerals . Its composition varies widely because of isomorphous replacement (solid solution), and its general formula can be written as XY 3 Z 6 (T 6 O 18 )(BO 3 ) 3 V 3 W , where: Mineral species that were named before

1541-633: Is considerably heavier than citrine (about 25% per volume) and this difference in weight can be used to distinguish two stones of equal volume. Also, if the volume of a given stone can be determined, its weight if it were topaz can be established and then checked with a sensitive scale. Likewise, glass stones are also much lighter than equally sized topaz. A variety of impurities and treatments may make topaz wine red, pale gray, reddish-orange, pale green, or pink (rare), and opaque to translucent/transparent. The pink and red varieties come from chromium replacing aluminium in its crystalline structure. Imperial topaz

1608-448: Is diagnostic for this mineral. The 2V optical angle in topaz can range from 48° to 69.5°. Low fluorine content yields a smaller angle and high fluorine content yields a larger angle. Topaz in its natural state is colorless, often with a greyish cast. It also occurs as a golden brown to yellow color which makes it sometimes confused with citrine , a less valuable gemstone. The specific gravity of all shades of topaz, however, means that it

1675-496: Is found. Some fine gems and specimen material have been produced in the United States, with the first discoveries in 1822, in the state of Maine . California became a large producer of tourmaline in the early 1900s. The Maine deposits tend to produce crystals in raspberry pink-red as well as minty greens. The California deposits are known for bright pinks, as well as bicolors. During the early 1900s, Maine and California were

1742-585: Is heat treated and irradiated to produce a more desired darker blue. Mystic topaz is a colorless topaz that has been artificially coated via a vapor deposition process giving it a rainbow effect on its surface. Although very hard, topaz must be treated with greater care than some other minerals of similar hardness (such as corundum ) because of a weakness of atomic bonding of the stone's molecules along one or another axial plane (whereas diamonds, for example, are composed of carbon atoms bonded to each other with equal strength along all of its planes). This gives topaz

1809-436: Is recommended to search for a stone that the seller knows the origin of. If the seller cannot produce information about the locality and mine that the topaz was collected from, it is likely that it was collected unethically. Topaz is an accessory mineral to felsic igneous, sedimentary, and hydrothermally altered rocks. The crystal structure of topaz alternates between sheets of (F, OH) 2 O and O along (010) with Al occupying

1876-505: Is responsible for the deepening of the pink to red color. Opaque black schorl and yellow tsilaisite are idiochromatic tourmaline species that have high magnetic susceptibilities due to high concentrations of iron and manganese respectively. Most gem-quality tourmalines are of the elbaite species. Elbaite tourmalines are allochromatic, deriving most of their color and magnetic susceptibility from schorl (which imparts iron) and tsilaisite (which imparts manganese). Red and pink tourmalines have

1943-573: Is the sodium magnesium rich tourmaline endmember. Uvite, in comparison, is a calcium magnesium tourmaline. Dravite forms multiple series, with other tourmaline members, including schorl and elbaite. The name dravite was used for the first time by Gustav Tschermak (1836–1927), Professor of Mineralogy and Petrography at the University of Vienna , in his book Lehrbuch der Mineralogie (published in 1884) for magnesium -rich (and sodium -rich) tourmaline from village Dobrova near Unterdrauburg in

2010-644: Is the world's largest cut tourmaline. Owned by Billionaire Business Enterprises, it was presented in Montreal , Quebec , Canada , on 14 October 2009. In the late 1990s, copper-containing tourmaline was found in Nigeria . The material was generally paler and less saturated than the Brazilian materials, although the material generally was much less included. A more recent African discovery from Mozambique has also produced tourmaline colored by copper, similar to

2077-510: Is usually believed to be derived (via Old French : Topace and Latin : Topazius) from the Greek Τοπάζιος (Topázios) or Τοπάζιον (Topázion), from Τοπαζος. This is the ancient name of St. John's Island in the Red Sea which was difficult to find and from which a yellow stone (now believed to be chrysolite : yellowish olivine ) was mined in ancient times. The name topaz was first applied to

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2144-455: Is yellow, pink (rare, if natural), or pink-orange. Brazilian imperial topaz can often have a bright yellow to deep golden brown hue, sometimes even violet. Many brown or pale topazes are treated to make them bright yellow, gold, pink, or violet colored. Some imperial topaz stones can fade from exposure to sunlight for an extended period of time. Naturally occurring blue topaz is quite rare. Typically, colorless, gray, or pale yellow and blue material

2211-645: The Bible , including the King James Version , mention topaz. However, because these translations as topaz all derive from the Septuagint translation topazi[os] , which referred to a yellow stone that was not topaz, but probably chrysolite ( chrysoberyl or peridot ), topaz is likely not meant here. An English superstition also held that topaz cured lunacy . The ancient Romans believed that topaz provided protection from danger while traveling. During

2278-797: The Drava river area, Carinthia , Austro-Hungarian Empire . Today this tourmaline locality (type locality for dravite) at Dobrova (near Dravograd ), is a part of the Republic of Slovenia . Tschermak gave this tourmaline the name dravite, for the Drava river area, which is the district along the Drava River (in German: Drau , in Latin : Drave ) in Austria and Slovenia. The chemical composition which

2345-585: The German language were "Schurel", "Schörle", and "Schurl". Beginning in the 18th century, the name Schörl was mainly used in the German-speaking area. In English, the names shorl and shirl were used in the 18th century. In the 19th century the names common schorl , schörl , schorl and iron tourmaline were the English words used for this mineral. Dravite , also called brown tourmaline ,

2412-512: The carnelian gemstones. Brightly colored Ceylonese gem tourmalines were brought to Europe in great quantities by the Dutch East India Company to satisfy a demand for curiosities and gems. Tourmaline was sometimes called the "Ceylonese Magnet" because it could attract and then repel hot ashes due to its pyroelectric properties. Tourmalines were used by chemists in the 19th century to polarize light by shining rays onto

2479-456: The state gemstone of the U.S. state of Utah . Blue topaz is the state gemstone of the US state of Texas . The 4th wedding anniversary gem is blue topaz and the 23rd is imperial topaz. Synthetic topaz can be produced using a method that includes the thermal hydrolysis of SiO 2 and AlF 3 . When these compounds are heated to temperatures of 750° to 850 °C topaz is formed. Another method uses

2546-525: The Brazilian paraiba. The Mozambique paraiba material usually is more intensely colored than the Nigerian and Mozambique Paraiba tourmaline have similar colors to the Brazilian Paraiba, but the prices are relatively cheaper, better clarity and larger sizes. In recent years the pricing of these beautiful gemstones has increased significantly. Another highly valuable variety is chrome tourmaline,

2613-668: The Czech Republic, Germany, Norway, Pakistan, Italy, Sweden, Japan, Brazil, Mexico; Flinders Island , Australia; Nigeria and the United States. Topaz was found around the time of the 1700s in a pegmatite formation within the central Urals Mountains in Russia. Brazil is one of the largest producers of topaz, some clear topaz crystals from Brazilian pegmatites can reach boulder size and weigh hundreds of pounds. The Topaz of Aurangzeb , observed by Jean Baptiste Tavernier weighed 157.75 carats (31.550 g). The American Golden Topaz ,

2680-557: The IMA was founded in 1958 do not have an IMA number. The IMA commission on new mineral names published a list of approved symbols for each mineral species in 2021. A revised nomenclature for the tourmaline group was published in 2011. Tourmaline is a six-member ring cyclosilicate having a trigonal crystal system. It occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section, often with curved striated faces. The style of termination at

2747-484: The Middle Ages, it was believed that attaching the topaz to the left arm protected the owner from any curse and warded off the evil eye . It was also believed that wearing topaz increased body heat, which would enable people to relieve a cold or fever. In Europe during the Middle Ages, topaz was believed to enhance mental powers. In India, people believed topaz granted beauty, intelligence, and longevity when worn over

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2814-456: The anion would be just neutral silica [SiO 2 ] n . Replacement of one in every four silicon atoms by an aluminum atom results in the anion [AlSi 3 O 8 ] n , whose charge is neutralized by the potassium cations K . In mineralogy , silicate minerals are classified into seven major groups according to the structure of their silicate anion: Tectosilicates can only have additional cations if some of

2881-414: The basic structural unit is not a unit cell : The actual unit cell of this structure includes portions of several units belonging to adjacent columns. Tourmaline has a variety of colors. Iron-rich tourmalines are usually black to bluish-black to deep brown, while magnesium-rich varieties are brown to yellow, and lithium-rich tourmalines are almost any color: blue, green, red, yellow, pink, etc. Rarely, it

2948-599: The collection of Kimberly Klosterman and on display at the Cincinnati Art Museum . Some forms of tourmaline are dichroic ; they change color when viewed from different directions. The pink color of tourmalines from many localities is the result of prolonged natural irradiation. During their growth, these tourmaline crystals incorporated Mn and were initially very pale. Due to natural gamma ray exposure from radioactive decay of K in their granitic environment, gradual formation of Mn ions occurs, which

3015-443: The ends of crystals is sometimes asymmetrical, called hemimorphism. Small slender prismatic crystals are common in a fine-grained granite called aplite , often forming radial daisy-like patterns. Tourmaline is distinguished by its three-sided prisms; no other common mineral has three sides. Prisms faces often have heavy vertical striations that produce a rounded triangular effect. Tourmaline is rarely perfectly euhedral . An exception

3082-585: The formula (Si 2 x O 5 x ) or a 2:5 ratio. The Nickel–Strunz classification is 09.C. Possible ring sizes include: Some example minerals are: The ring in axinite contains two B and four Si tetrahedra and is highly distorted compared to the other 6-member ring cyclosilicates. Inosilicates (from Greek ἴς is [genitive: ἰνός inos ] 'fibre'), or chain silicates, have interlocking chains of silicate tetrahedra with either SiO 3 , 1:3 ratio, for single chains or Si 4 O 11 , 4:11 ratio, for double chains. The Nickel–Strunz classification

3149-530: The gem and treating it to achieve the desired color. Mining for topaz can cause some environmental concerns mostly associated with larger-scale operations. The introduction of a large open pit mine into an environment leads to modification of the land around it to make it accessible to workers. After use of such mines is over, they are often refilled with loose sediments left over from the mining process. These loose sediments can be washed away to other areas, cutting off water features, destroying farmland, and creating

3216-455: The gem. The waste material is discarded using large machines to transport it away while the valuable ore is washed and sorted to recover the topaz gems. In smaller-scale mines, dry sieving is used in alluvial environments by shoveling the material into sieves to separate the gems from unwanted dust and debris. The topaz can then be selected by hand from the remaining material. Mined topaz is then sent to be processed for use in jewelry by polishing

3283-417: The heart. Topaz is a gemstone . In cut and polished form, it is used to make jewelry or other adornments. Lower quality topaz is commonly used as an abrasive material due to its hardness and it is used to produce refractory materials for high temperature environments. Topaz can be used as a flux in steel production. Using topaz as a refectory material does have some health and environmental concerns due to

3350-409: The largest and most important class of minerals and make up approximately 90 percent of Earth's crust . In mineralogy , silica (silicon dioxide, SiO 2 ) is usually considered a silicate mineral rather than an oxide mineral . Silica is found in nature as the mineral quartz , and its polymorphs . On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as

3417-432: The lowest magnetic susceptibilities among the elbaites, while tourmalines with bright yellow, green and blue colors are the most magnetic elbaites. Dravite species such as green chromium dravite and brown dravite are diamagnetic. A handheld neodymium magnet can be used to identify or separate some types of tourmaline gems from others. For example, blue indicolite tourmaline is the only blue gemstone of any kind that will show

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3484-465: The mineral now known by that name in 1737. Ancient Sri Lanka ( Tamraparni ) exported topazes to Greece and ancient Egypt, which led to the etymologically related names of the island by Alexander Polyhistor ( Topazius ) and the early Egyptians ( Topapwene ) – "land of the Topaz". Pliny said that Topazos is a legendary island in the Red Sea and the mineral "topaz" was first mined there. Alternatively,

3551-509: The mines can also be exposed to harmful chemicals and heavy metals that can impact their health. For income, there can be an unequal dispersal of the funds made from gem mining between land owners, laborers, and the operators of the mine. In illegal mining operations, there can be more money given to miners, however, these operations have fewer regulations and more dangerous environments. Silicate mineral Silicate minerals are rock-forming minerals made up of silicate groups. They are

3618-463: The new alkali element lithium (Li) was determined in 1818 by Johan August Arfwedson for the first time. Elba Island , Italy , was one of the first localities where colored and colorless Li-tourmalines were extensively chemically analysed. In 1850, Karl Friedrich August Rammelsberg described fluorine (F) in tourmaline for the first time. In 1870, he proved that all varieties of tourmaline contain chemically bound water. In 1889, Scharitzer proposed

3685-399: The octahedral sites and Si in the tetrahedral sites. Fluorine can be substituted by hydroxide in topaz by up to 30 mol.% in nature and hydroxide-dominating topaz can be made in laboratories but has not been found in nature. On occasion, cavities can be found within topaz and they are filled with a liquid called brewsterlinite. Brewsterlinite was discovered by David Brewster upon heating

3752-510: The oxide has a coordination number of two. Some silicon centers may be replaced by atoms of other elements, still bound to the four corner oxygen corners. If the substituted atom is not normally tetravalent, it usually contributes extra charge to the anion, which then requires extra cations . For example, in the mineral orthoclase [KAlSi 3 O 8 ] n , the anion is a tridimensional network of tetrahedra in which all oxygen corners are shared. If all tetrahedra had silicon centers,

3819-554: The paraiba tourmaline from Brazil does not actually come from Paraíba , but the neighboring state of Rio Grande do Norte . Material from Rio Grande do Norte is often somewhat less intense in color, but many fine gems are found there. It was determined that the element copper was important in the coloration of the stone. A large bluish-green tourmaline from Paraiba, measuring 36.44 mm × 33.75 mm × 21.85 mm (1.43 in × 1.33 in × 0.86 in) and weighing 191.87 carats (1.3536 oz; 38.374 g),

3886-421: The production of fluorine as a byproduct of calcining topaz. Topaz is a part of the second rank of gemstones, or semiprecious stones, accompanying aquamarine , morganite , and tourmaline . The first rank of gemstones, or precious stones, includes ruby , sapphire , diamond , and emerald . Orange topaz, also known as precious topaz, is the birthstone for the month of November, the symbol of friendship, and

3953-441: The silicates and the metals are strong, polar-covalent bonds. Silicate anions ([SiO 2+ n ] ) are invariably colorless, or when crushed to a fine powder, white. The colors of silicate minerals arise from the metal component, commonly iron. In most silicate minerals, silicon is tetrahedral, being surrounded by four oxides. The coordination number of the oxides is variable except when it bridges two silicon centers, in which case

4020-541: The silicon is replaced by an atom of lower valence such as aluminum. Al for Si substitution is common. Nesosilicates (from Greek νῆσος nēsos 'island'), or orthosilicates, have the orthosilicate ion , present as isolated (insular) [SiO 4 ] tetrahedra connected only by interstitial cations . The Nickel–Strunz classification is 09.A –examples include: Sorosilicates (from Greek σωρός sōros 'heap, mound') have isolated pyrosilicate anions Si 2 O 7 , consisting of double tetrahedra with

4087-636: The substitution of (OH) by F in red Li-tourmaline from Sušice , Czech Republic . In 1914, Vladimir Vernadsky proposed the name Elbait for lithium-, sodium-, and aluminum-rich tourmaline from Elba Island, Italy, with the simplified formula (Li,Na)HAl 6 B 2 Si 4 O 21 . Most likely the type material for elbaite was found at Fonte del Prete, San Piero in Campo, Campo nell'Elba , Elba Island, Province of Livorno , Tuscany , Italy . In 1933 Winchell published an updated formula for elbaite, H 8 Na 2 Li 3 Al 3 B 6 Al 12 Si 12 O 62 , which

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4154-517: The word topaz may be related to the Sanskrit word तपस् "tapas", meaning "heat" or "fire". Nicols, the author of one of the first systematic treatises on minerals and gemstones, dedicated two chapters to the topic in 1652. In the Middle Ages , the name topaz was used to refer to any yellow gemstone, but in modern times it denotes only the silicate described above. Many English translations of

4221-544: The world's largest producers of gem tourmalines. The Empress Dowager Cixi of China loved pink tourmaline and bought large quantities for gemstones and carvings from the then new Himalaya Mine, located in San Diego County , California. It is not clear when the first tourmaline was found in California. Native Americans have used pink and green tourmaline as funeral gifts for centuries. The first documented case

4288-486: Was given by Tschermak in 1884 for this dravite approximately corresponds to the formula NaMg 3 (Al,Mg) 6 B 3 Si 6 O 27 (OH) , which is in good agreement (except for the OH content) with the endmember formula of dravite as known today. Dravite varieties include the deep green chromium dravite and the vanadium dravite. A lithium-tourmaline elbaite was one of three pegmatitic minerals from Utö , Sweden , in which

4355-593: Was in 1890 when Charles Russel Orcutt found pink tourmaline at what later became the Stewart Mine at Pala, California in San Diego County . Almost every color of tourmaline can be found in Brazil, especially in Minas Gerais and Bahia . The new type of tourmaline, which soon became known as paraiba tourmaline, came in blue and green. Brazilian paraiba tourmaline usually contains abundant inclusions. Much of

4422-461: Was the fine dravite tourmalines of Yinnietharra , in western Australia. The deposit was discovered in the 1970s, but is now exhausted. All hemimorphic crystals are piezoelectric , and are often pyroelectric as well. A crystal of tourmaline is built up of units consisting of a six-member silica ring that binds above to a large cation, such as sodium. The ring binds below to a layer of metal ions and hydroxyls or halogens, which structurally resembles

4489-485: Was then named "Schorl" (or minor variants of this name), and the village had a nearby tin mine where, in addition to cassiterite , black tourmaline was found. The first description of schorl with the name "schürl" and its occurrence (various tin mines in the Ore Mountains ) was written by Johannes Mathesius (1504–1565) in 1562 under the title "Sarepta oder Bergpostill". Up to about 1600, additional names used in

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