Topaz
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Topaz is a
silicate mineral Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...
of
aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...
and
fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...
with the
chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...
Al Si O( F, OH). 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. Although it is often associated with golden yellow and blue, it comes in a variety of colors, including colorless. The rarest are natural pinks, reds, and delicate golden oranges, sometimes with pink hues. Topaz is a
nesosilicate Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
. It is one of the hardest naturally occurring minerals and has a relatively low index of refraction. It occurs in many places in the world.


Etymology

The name "topaz" is usually believed to be derived (via
Old French Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intelligib ...
: Topace and
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
: Topazus) from the
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
''Τοπάζιος'' (Topázios) or ''Τοπάζιον'' (Topázion), from Τοπαζος. This is the ancient name of St. John's Island in the
Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...
which was difficult to find and from which a yellow stone (now believed to be chrysolite: yellowish
olivine The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...
) was mined in ancient times . The name ''topaz'' was first applied to the mineral now known by that name in 1737. Ancient Sri Lanka (
Tamraparni Tamraparni (Sanskrit for "with copper leaves" or "red-leaved") is an older name for multiple distinct places, including Sri Lanka, Tirunelveli in India, and the Thamirabarani River that flows through Tirunelveli. As a name for Sri Lanka The r ...
) exported native oriental topazes to Greece and ancient Egypt, which led to the etymologically related names of the island by
Alexander Polyhistor Lucius Cornelius Alexander Polyhistor ( grc, Ἀλέξανδρος ὁ Πολυΐστωρ; flourished in the first half of the 1st century BC; also called Alexander of Miletus) was a Greek scholar who was enslaved by the Romans during the Mithri ...
(''Topazius'') and the early Egyptians (''Topapwene'') – "land of the Topaz".
Pliny Pliny may refer to: People * Pliny the Elder (23–79 CE), ancient Roman nobleman, scientist, historian, and author of ''Naturalis Historia'' (''Pliny's Natural History'') * Pliny the Younger (died 113), ancient Roman statesman, orator, w ...
said that Topazos is a ''legendary'' island in the
Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...
and the mineral "topaz" was first mined there. Alternatively, the word ''topaz'' may be related to the Sanskrit word तपस् "tapas", meaning "heat" or "fire".


History

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 In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
, 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 the
Bible The Bible (from Koine Greek , , 'the books') is a collection of religious texts or scriptures that are held to be sacred in Christianity, Judaism, Samaritanism, and many other religions. The Bible is an anthologya compilation of texts of a ...
, including the
King James Version The King James Version (KJV), also the King James Bible (KJB) and the Authorized Version, is an Bible translations into English, English translation of the Christian Bible for the Church of England, which was commissioned in 1604 and publis ...
, mention ''topaz''. However, because these translations as ''topaz'' all derive from the
Septuagint The Greek Old Testament, or Septuagint (, ; from the la, septuaginta, lit=seventy; often abbreviated ''70''; in Roman numerals, LXX), is the earliest extant Greek translation of books from the Hebrew Bible. It includes several books beyond th ...
translation ''topazi s', which referred to a yellow stone that was not topaz, but probably ''chrysolite'' (
chrysoberyl The mineral or gemstone chrysoberyl is an aluminate of beryllium with the formula Be Al2 O4. The name chrysoberyl is derived from the Greek words χρυσός ''chrysos'' and βήρυλλος ''beryllos'', meaning "a gold-white spar". Despite ...
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 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 The Evil Eye ( grc, ὀφθαλμὸς βάσκανος; grc-koi, ὀφθαλμὸς πονηρός; el, (κακό) μάτι; he, עַיִן הָרָע, ; Romanian: ''Deochi''; it, malocchio; es, mal de ojo; pt, mau-olhado, olho gordo; ar ...
. 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.


Gemstone

Topaz is a gemstone. In cut and polished form, it is used to make jewellery or other adornments. It also has other uses. Orange topaz, also known as precious topaz, is the conventional birthstone for November, the symbol of friendship and the state gemstone of the U.S. state of
Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
. Blue topaz is the state gemstone of the US state of
Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
.


Characteristics

Topaz in its natural state is colorless, often with a greyish cast. It also occurs as a golden brown to yellow which makes it sometimes confused with citrine, a less valuable gemstone. The
specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest ...
of all shades of topaz, however, means that it 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 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 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 on 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 is heat treated and
irradiated Irradiation is the process by which an object is exposed to radiation. The exposure can originate from various sources, including natural sources. Most frequently the term refers to ionizing radiation, and to a level of radiation that will serve ...
to produce a more desired darker blue. Mystic topaz is colorless topaz which has been artificially coated via a
vapor deposition Vacuum deposition is a group of processes used to deposit layers of material atom-by-atom or molecule-by-molecule on a solid surface. These processes operate at pressures well below atmospheric pressure (i.e., vacuum). The deposited layers can r ...
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 Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the pres ...
) 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 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 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 Bromoform (CHBr3) is a brominated organic solvent, colorless liquid at room temperature, with a high refractive index, very high density, and sweet odor is similar to that of chloroform. It is one of the four haloforms, the others being fluoroform, ...
or
methylene iodide Diiodomethane or methylene iodide, commonly abbreviated "MI", is an organoiodine compound. Diiodomethane is a colorless liquid; however, it decomposes upon exposure to light liberating iodine, which colours samples brownish. It is slightly solu ...
. Quartz will invariably float in these solutions, whereas topaz will sink.


Localities and occurrence

Topaz is commonly associated with
silicic Silicic is an adjective to describe magma or igneous rock rich in silica. The amount of silica that constitutes a silicic rock is usually defined as at least 63 percent. Granite and rhyolite are the most common silicic rocks. Silicic is the grou ...
igneous rocks of the
granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...
and
rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral ...
type. It typically crystallizes in granitic
pegmatites A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic co ...
or in vapor cavities in rhyolite lava flows including those at
Topaz Mountain Topaz Mountain is a summit in the Thomas Range of Utah, east of the Thomas caldera. The summit and surrounding area are known for their abundances of semiprecious minerals including topaz, red beryl and opal. Geology and geography Topaz Mounta ...
in western Utah and
Chivinar Chivinar is a high Late Miocene volcano in Northwest Argentina. The volcano is noted for having erupted rhyolites containing topaz in its early stage of evolution, the only known occurrence of such in South America. This topaz did form during t ...
in South America. It can be found with
fluorite Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs sca ...
and cassiterite in various areas including the
Ural Ural may refer to: *Ural (region), in Russia and Kazakhstan *Ural Mountains, in Russia and Kazakhstan *Ural (river), in Russia and Kazakhstan * Ual (tool), a mortar tool used by the Bodo people of India *Ural Federal District, in Russia *Ural econ ...
and
Ilmensky Mountains The Ilmensky Mountains (russian: links=no, Ильменские горы, translit=Il'menskiye gory) are located in the Southern Urals in the Chelyabinsk Oblast on the administrative territory of Miass in Chebarkulsky and Argayashsky districts. ...
of
Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
, in
Afghanistan Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is bordere ...
,
Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
,
Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...
,
Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
,
Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...
,
Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
,
Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...
,
Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...
,
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
,
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
,
Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
;
Flinders Island Flinders Island, the largest island in the Furneaux Group, is a island in the Bass Strait, northeast of the island of Tasmania. Flinders Island was the place where the last remnants of aboriginal Tasmanian population were exiled by the colo ...
,
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
;
Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
and the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. 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 Muhi al-Din Muhammad (; – 3 March 1707), commonly known as ( fa, , lit=Ornament of the Throne) and by his regnal title Alamgir ( fa, , translit=ʿĀlamgīr, lit=Conqueror of the World), was the sixth emperor of the Mughal Empire, ruling ...
, observed by
Jean Baptiste Tavernier Jean-Baptiste Tavernier (1605–1689) was a 17th-century French gem merchant and traveler. Tavernier, a private individual and merchant traveling at his own expense, covered, by his own account, 60,000 leagues in making six voyages to Persia ...
weighed . The American Golden Topaz, a more recent gem, weighed a massive . Large, vivid blue topaz specimens from the St. Anns mine in
Zimbabwe Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Botswana to the south-west, Zambia to the north, and Mozam ...
were found in the late 1980s. Colorless and light-blue varieties of topaz are found in Precambrian granite in
Mason County, Texas Mason County is a rural county located on the Edwards Plateau in the U.S. state of Texas. At the 2020 census, its population was 3,953. Its county seat is Mason. The county is named for Fort Mason, which was located in the county. History * ...
within the
Llano Uplift The Llano Uplift is a geologically ancient, low geologic dome that is about in diameter and located mostly in Llano, Mason, San Saba, Gillespie, and Blanco counties, Texas. It consists of an island-like exposure of Precambrian igneous and m ...
. There is no commercial mining of topaz in that area. It is possible to synthesize topaz. File:TopazMountainByPhilKonstantin.jpg,
Topaz Mountain Topaz Mountain is a summit in the Thomas Range of Utah, east of the Thomas caldera. The summit and surrounding area are known for their abundances of semiprecious minerals including topaz, red beryl and opal. Geology and geography Topaz Mounta ...
, Utah, United States File:Topaz-200562.jpg, Red topaz from Tepetate, Municipio de Villa de Arriaga, San Luis Potosí, Mexico File:Large Topaz Gemstones.jpg, Facet cut topaz gemstones in various colors File:YellowTopaz.jpeg, Yellow topaz in stepped kite-shaped cut File:TOPAZE9.jpg, Imperial Topaz of Minas Gerais


See also

*
Agate Agate () is a common rock formation, consisting of chalcedony and quartz as its primary components, with a wide variety of colors. Agates are primarily formed within volcanic and metamorphic rocks. The ornamental use of agate was common in Anci ...
*
Beryl Beryl ( ) is a mineral composed of beryllium aluminium silicate with the chemical formula Be3Al2Si6O18. Well-known varieties of beryl include emerald and aquamarine. Naturally occurring, hexagonal crystals of beryl can be up to several ...
*
Opal Opal is a hydrated amorphous form of silica (SiO2·''n''H2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline forms ...


References


External links


Topaz
from the International Colored Gemstone Association

Utah Geological Survey * {{Authority control Aluminium minerals Gemstones Nesosilicates Orthorhombic minerals Minerals in space group 62 Luminescent minerals