Sylvanite

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Sylvanite
Sylvanite ((Au,Ag)2Te4), Cripple Creek Diatreme.jpg
Sylvanite from the Cripple Creek mining district
General
Category Telluride mineral
Formula
(repeating unit)
(Ag,Au)Te2
IMA symbol Syv [1]
Strunz classification 2.EA.05
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group P2/c
Identification
Formula mass 429.89 g/mol
ColorSilver-grey, silver-white
Crystal habit Massive to crystalline
Cleavage Perfect on the {010}
Fracture Uneven
Tenacity Brittle
Mohs scale hardness1.5–2
Luster Metallic
Streak Steel grey
Diaphaneity Opaque
Specific gravity 8.2
Density 8.1
Optical propertiesAnisotropic
Pleochroism None
Ultraviolet fluorescence None
References [2] [3] [4]

Sylvanite or silver gold telluride, chemical formula (Ag,Au)Te 2, is the most common telluride of gold.

Contents

Properties

The gold:silver ratio varies from 3:1 to 1:1. It is a metallic mineral with a color that ranges from a steely gray to almost white. It is closely related to calaverite, which is more purely gold telluride with 3% silver. Sylvanite crystallizes in the monoclinic 2/m system. Crystals are rare and it is usually bladed or granular. It is very soft with a hardness of 1.5–2. It has a high relative density of 8–8.2. Sylvanite is photosensitive and can accumulate a dark tarnish if it is exposed to bright light for too long.

Occurrence

Sylvanite is found in Transylvania, from which its name is partially derived. [5] It is also found and mined in Australia in the East Kalgoorlie district. In Canada it is found in the Kirkland Lake Gold District, Ontario and the Rouyn District, Quebec. In the United States it occurs in California and in Colorado where it was mined as part of the Cripple Creek ore deposit. Sylvanite is associated with native gold, quartz, fluorite, rhodochrosite, pyrite, acanthite, nagyagite, calaverite, krennerite, and other rare telluride minerals. It is found most commonly in low temperature hydrothermal vein deposits.

Use

Sylvanite represents a minor ore of gold and tellurium. Sylvanium, an obsolete term for tellurium, derived its name from sylvanite. [6]

Related Research Articles

<span class="mw-page-title-main">Tellurium</span> Chemical element with atomic number 52 (Te)

Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in its native form as elemental crystals. Tellurium is far more common in the Universe as a whole than on Earth. Its extreme rarity in the Earth's crust, comparable to that of platinum, is due partly to its formation of a volatile hydride that caused tellurium to be lost to space as a gas during the hot nebular formation of Earth.

<span class="mw-page-title-main">Petzite</span> Telluride mineral

The mineral petzite, Ag3AuTe2, is a soft, steel-gray telluride mineral generally deposited by hydrothermal activity. It forms isometric crystals, and is usually associated with rare tellurium and gold minerals, often with silver, mercury, and copper.

<span class="mw-page-title-main">Calaverite</span> Telluride of gold

Calaverite, or gold telluride, is an uncommon telluride of gold, a metallic mineral with the chemical formula AuTe2, with approximately 3% of the gold replaced by silver. It was first discovered in Calaveras County, California in 1861, and was named for the county in 1868.

The telluride ion is the anion Te2− and its derivatives. It is analogous to the other chalcogenide anions, the lighter O2−, S2−, and Se2−, and the heavier Po2−.

<span class="mw-page-title-main">Krennerite</span> Gold telluride mineral

Krennerite is an orthorhombic gold telluride mineral which can contain variable amounts of silver in the structure. The formula is AuTe2, but specimen with gold substituted by up to 24% with silver have been found ([Au0.77Ag0.24]Te2). Both of the chemically similar gold-silver tellurides, calaverite and sylvanite, are in the monoclinic crystal system, whereas krennerite is orthorhombic.

<span class="mw-page-title-main">Rickardite</span>

Rickardite is a telluride mineral, a copper telluride (Cu7Te5) or Cu3-x (x = 0 to 0.36)Te2. It was first described for an occurrence in the Good Hope Mine, Vulcan district, Gunnison County, Colorado, US, and named for mining engineer Thomas Arthur Rickard (1864–1953). It is a low temperature hydrothermal mineral that occurs associated with vulcanite, native tellurium, cameronite, petzite, sylvanite, berthierite, pyrite, arsenopyrite and bornite.

Weissite is a telluride mineral, a copper telluride. Its chemical formula is Cu
2−x
Te
. Weissite has hexagonal crystal structure. Its specific gravity is 6 and its Mohs hardness is 3. Occurrence is in Gunnison County, Colorado, Arizona and New Mexico in the United States. It is also reported from Kalgoorlie, Western Australia and Dalarna and Värmland, Sweden.

<span class="mw-page-title-main">Tellurobismuthite</span>

Tellurobismuthite, or tellurbismuth, is a telluride mineral: bismuth telluride (Bi2Te3). It crystallizes in the trigonal system. There are natural cleavage planes in the (0001) direction as the crystal is effectively lamellar (layered) in that plane. The Mohs hardness is 1.5 – 2 and the specific gravity is 7.815. It is a dull grey color, which exhibits a splendent luster on fresh cleavage planes.

<span class="mw-page-title-main">Native metal</span> Form of metal

A native metal is any metal that is found pure in its metallic form in nature. Metals that can be found as native deposits singly or in alloys include antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, manganese, molybdenum, nickel, niobium, rhenium, tantalum, tellurium, tin, titanium, tungsten, vanadium, and zinc, as well as the gold group and the platinum group. Among the alloys found in native state have been brass, bronze, pewter, German silver, osmiridium, electrum, white gold, silver-mercury amalgam, and gold-mercury amalgam.

<span class="mw-page-title-main">Nagyágite</span> Sulfide mineral

Nagyágite is a rare sulfide mineral with known occurrence associated with gold ores. Nagyágite crystals are opaque, monoclinic and dark grey to black coloured.

<span class="mw-page-title-main">Vulcanite</span> Copper telluride mineral

Vulcanite is a rare copper telluride mineral. The mineral has a metallic luster, and has a green or bronze-yellow tint. It has a hardness between 1 and 2 on the Mohs scale. Its crystal structure is orthorhombic.

Gold chalcogenides are compounds formed between gold and one of the chalcogens, elements from group 16 of the periodic table: oxygen, sulfur, selenium, or tellurium.

<span class="mw-page-title-main">Coloradoite</span> Rare telluride ore

Coloradoite, also known as mercury telluride (HgTe), is a rare telluride ore associated with metallic deposit. Gold usually occurs within tellurides, such as coloradoite, as a high-finess native metal.

<span class="mw-page-title-main">Zemannite</span>

Zemannite is a very rare oxide mineral with the chemical formula Mg0.5ZnFe3+[TeO3]3·4.5H2O. It crystallizes in the hexagonal crystal system and forms small prismatic brown crystals. Because of the rarity and small crystal size, zemannite has no applications and serves as a collector's item.

<span class="mw-page-title-main">Stützite</span> Telluride mineral

Stützite or stuetzite is a silver telluride mineral with formula: Ag5−xTe3 (with x = 0.24 to 0.36) or Ag7Te4.

<span class="mw-page-title-main">Rodalquilarite</span>

Rodalquilarite is a rare iron tellurite chloride mineral with formula H3Fe3+2(Te4+O3)4Cl or Fe2(TeO2OH)3(TeO3)Cl. Rodalquilarite crystallizes in the triclinic system and typically occurs as stout green prisms and encrustations.

Telluro-silver glance — is a trivial name given by collectors and mineral dealers, miners, geologists and other professions to at least two ore mineralsrare ore minerals, tellurides of silver. It may refer to:

Telluric silver — is an obsolete trivial name, which collectors and mineral traders, miners, geologists and representatives of other applied professions actually applied to several rare ore minerals, tellurides of silver, as well as to chemical compounds of similar composition. It may refer to:

Marianna Sergeevna Bezsmertnaya, née Yurkevich was a Soviet and Russian geologist, mineralogist, petrographer and petrologist, candidate of geological and mineralogical sciences (1957), developer of new methods for diagnosing minerals, active participant and author of the discovery of a number of new minerals. For 25 years, he has been a leading employee of the Moscow Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements, the author of new methods for determining minerals. In the late 1950s — early 1960s, she re-checked and revised the mineralogical collection of the institute.

Bezsmertnovite, less often bessmertnovite (Russian: Безсмертновит) is a very rare supergene mineral of the sulfide class, complex in composition: mixed plumbotelluride of gold, copper, iron, silver from the bilibinskite group with the calculation formula Au4Cu(Te,Pb).

References

  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. Sylvanite: Sylvanite mineral information and data
  3. Sylvanite Mineral Data
  4. "Sylvanite (Silver Gold Telluride)". Archived from the original on 2004-06-30. Retrieved 2004-06-19.
  5. Jolyon, Ralph. "Sylvanite". mindat.org. Retrieved 18 January 2013.
  6. Klein, Cornelis (1985), Hurlbut, Cornelius S. (ed.), Manual of Mineralogy: (after James D. Dana) (20th ed.), Albuquerque, US-NM: Wiley, p. 290, ISBN   0-471-80580-7 , retrieved 2017-06-28

Chisholm, Hugh, ed. (1911). "Sylvanite"  . Encyclopædia Britannica (11th ed.). Cambridge University Press.