Hessite

Hessite
General
Category	Sulfide minerals
Formula (repeating unit)	Ag2Te
Strunz classification	2.BA.30c
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	P21/c
Unit cell	a = 8.13, b = 4.48 c = 8.09 [Å]; β = 112.9°; Z = 4
Identification
Color	Lead-grey, steel-grey
Cleavage	Indistinct on {100}
Tenacity	Sectile
Mohs scale hardness	2 - 3
Luster	Metallic
Streak	black
Diaphaneity	Opaque
Specific gravity	8.24 - 8.45
Optical properties	Anisotropic

Hessite is a mineral form of disilver telluride (Ag₂Te). It is a soft, dark grey telluride mineral which forms monoclinic crystals.

It is named after Germain Henri Hess (1802–1850).

Hessite is found in the US in Eagle County, Colorado and in Calaveras County, California and in many other locations.

Stützite (Ag₇Te₄) and empressite (AgTe) are related silver telluride minerals.

References

• webmineral.com entry
• Mindat.org entry