Carrollite from Kambove, Katanga. This specimen is 4.3 cm wide, with a 1.2 cm carrollite crystal partly covered by pyrite, between calcite crystals.
General
Category
Sulfide mineral Thiospinel group (Spinel structural group)
Formula (repeating unit)
CuCo2S4
IMA symbol
Cli[1]
Strunz classification
2.DA.05
Dana classification
2.10.1.2
Crystal system
Isometric
Crystal class
Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m)
Space group
Fd3m
Identification
Color
Light to dark gray, rarely tarnishes to copper red or violet gray
Crystal habit
Octahedral and cubic crystals, also massive, granular or compact
Twinning
{111} Polysynthetic or spinel twins[2]
Cleavage
Imperfect on {001}
Fracture
Conchoidal, subconchoidal or uneven
Tenacity
Very brittle
Mohs scale hardness
4.5 to 5.5
Luster
Metallic
Streak
Grey black
Diaphaneity
Opaque. R is 43% to 45% for lambda = 560 nm[3]
Specific gravity
4.5 to 4.8 measured, 4.83 calculated
Refractive index
n is not determined for an opaque mineral
Solubility
Minerals of the linneite group are partly etched by nitric acid, with slight effervescence.[2]
Other characteristics
Not radioactive, not fluorescent
References
[4][5][6][7]
Carrollite, CuCo2S4, is a sulfide of copper and cobalt, often with substantial substitution of nickel for the metal ions, and a member of the linnaeite group. It is named after the type locality in Carroll County, Maryland, US, at the Patapsco mine, Sykesville.[6]
Carrollite, CuCo2S4, is a sulfide of copper and cobalt, often with substantial substitution of nickel for the metal ions, and a member of the linnaeite...
2009 study of the ternary compound CuCo2S4 (a spinel mineral known as carrollite) that "was undertaken primarily to establish unequivocally the oxidation...
carrollite crystals of extraordinary size and quality. Some single crystals were almost as large as baseballs. In fact, many specimens of carrollite were...
cobaltite (CoAsS) in veins with smaltite, silver, nickel and calcite; carrollite (CuCo2S4) and linnaeite (Co3S4) as constituents of copper ore; and linnaeite...
oxocompounds, as is shown in the case of carrollite. Group members include: Cadmoindite – CdIn2S4 Carrollite – CuCo2S4 Fletcherite – Cu(Ni,Co)2S4 Greigite...
similar minerals. Its formation is likely related to the weathering of carrollite (CuCo2S4). In nature it is found coexisting with other minerals like smaltite...
Central area and to bornite-chalcopyrite at Mindola. Cobalt occurs as carrollite and cobaltiferous pyrite in approximately equal proportions. The mine...
(the Co analogue of pentlandite). Mixed metal sulfide minerals include carrollite (CuCo2S4) and siegenite (Co3−xNixS4). CoS is known as jaipurite. However...
Central area and to bornite-chalcopyrite at Mindola. Cobalt occurs as carrollite and cobaltiferous pyrite in approximately equal proportions. The mine...
(Old) Male Main (God) Quad 1850s? (named 1890) WW2 (became office space) Carrollites Corby Hall Male Main (God) Quad 1895 (1899 as dorm) 1936 (became priests'...
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