Krennerite is an orthorhombic

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile ...

telluride

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 ...

which can contain variable amounts of

silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...

in the structure. The formula is AuTe₂, but specimen with gold substituted by up to 24% with

have been found ( u_0.77Ag_0.24e₂). Both of the chemically similar gold-silver tellurides, calaverite and

sylvanite Sylvanite or silver gold telluride, chemical formula , is the most common telluride of gold. 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 c ...

, are in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic ...

crystal system, whereas krennerite is orthorhombic. The color varies from silver-white to brass-yellow. It has a

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 dens ...

of 8.62 and a

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

of 2.5. It occurs in high temperature,

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

environments. Krennerite was discovered in 1878 near the village of Săcărâmb,

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...

, and first described by the Hungarian

mineralogist Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proce ...

Joseph Krenner (1839–1920).

References

*G. Tunnell and K. J. Murata, American Mineralogist 35, 359-384 (1950).
Structure of Krennerite
retrieved 6-26-05

retrieved 6-26-05 Silver minerals Gold minerals Telluride minerals Orthorhombic minerals Minerals in space group 28 Minerals described in 1878 {{mineral-stub

See also

References