Berryite

Berryite is a mineral with the formula Pb₃(Ag,Cu)₅Bi₇S₁₆. It occurs as gray to blue-gray monoclinic prisms. It is opaque and has a metallic luster. It has a Mohs hardness of 3.5 and a specific gravity of 6.7.

Berryite
Black acicular crystals of the rare Pb-Ag sulfide from a Colorado locality: Mike Mine, San Juan County, Colorado, United States
General
Category	Mineral
Formula (repeating unit)	Cu3Ag2Pb3Bi7S16
IMA symbol	Bry^[1]
Strunz classification	2.HB.20d (10th)
Dana classification	3.6.15.1
Crystal system	Monoclinic
Crystal class	2/m (Prismatic)
Unit cell	1,445.93 Å^3
Identification
Colour	Bluish-grey, white, grey-white
Twinning	Repeated
Cleavage	Poor/indistinct
Mohs scale hardness	3.5
Luster	Metallic
Diaphaneity	Opaque
Specific gravity	6.7
Density	6.7 g/cm^3 (measured)
Pleochroism	Weak

It was first identified in 1965 using X-ray diffraction by mineralogist Leonard Gascoigne Berry (1914–1982). It is found in Park and San Juan counties in Colorado. It occurs in sulfide bearing quartz veins in Colorado and with siderite-rich cryolite in Ivigtut, Greenland.

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.

• Webmineral data
• Mindat with location data
• Mineral Data Publishing - PDF