Mineral Factbook

Sylvanite

AgAuTe4IMA symbol: Syvgrandfathered

Sylvanite is a sulfide or sulfosalt mineral with the formula AgAuTe4, crystallizing in the monoclinic system. It has a Mohs hardness of 1.5-2, typically white, gray or yellow in color, with a metallic luster, a specific gravity of 7.9-8.3. Its streak is white or gray.

Photos

Sylvanite specimen photo
Chatsam · CC BY-SA 3.0 · Commons
Sylvanite specimen photo
Vikent’eva, O.V.; Shilovskikh, V.V.; Shcherbakov, V.D.; Vikentyev, I.V.; Bortnikov, N.S. · CC BY 4.0 · Commons
Sylvanite specimen photo
Mai Seppel · CC BY-SA 4.0 · Commons
Sylvanite specimen photo
Kaarel Tiidus · CC BY-SA 4.0 · Commons

Crystallography

Crystal systemmonoclinic crystal systemWikidata (CC0)
Space groupP 1 2/c 1
Cell (Å, °)a = 8.94, b = 4.48, c = 14.59; α = 90, β = 145.43, γ = 90
Cell volume331.566 ų, Z = 2
Axial ratios1.9955:1:3.2567calculated from COD 9000026
Source structureCOD 9000026 (American Mineralogist, 1941)

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)3.042.982.1372.1192.072.24
I/I₀10040.330.725.318.115.5

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9000026; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)8.166 g/cm³calculated from COD 9000026
Hardness (Mohs)
1.75single sourceWikidata (CC0)
1.5-2single sourceDana, System of Mineralogy, 6th ed. (1892)
Specific gravity
7.9-8.3 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892)
Color
gray, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892)
Streak
gray, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892)
Luster
metallicsingle sourceDana, System of Mineralogy, 6th ed. (1892)

Chemistry (calculated)

Molecular weight815.23 g/molcalculated from the IMA formula
Composition (wt%)Ag 13.23%, Au 24.16%, Te 62.61%

Classification

Nickel-Strunz (10th)2.EA.05Wikidata (CC0)
Nickel-Strunz (9th)2.EA.05Wikidata (CC0)