Berryite

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Berryite
Black acicular crystals of the rare Pb-Ag sulfide from a Colorado locality: Mike Mine, San Juan County, Colorado, United States
General
CategoryMineral
Formula
(repeating unit)
Cu3Ag2Pb3Bi7S16
IMA symbolBry[1]
Strunz classification2.HB.20d (10th)
Dana classification3.6.15.1
Crystal systemMonoclinic
Crystal class2/m (Prismatic)
Unit cell1,445.93 Å3
Identification
ColourBluish-grey, white, grey-white
TwinningRepeated
CleavagePoor/indistinct
Mohs scale hardness3.5
LusterMetallic
DiaphaneityOpaque
Specific gravity6.7
Density6.7 g/cm3 (measured)
PleochroismWeak

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.

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

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  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.