Chvilevaite

Chvilevaite
General
CategorySulfide mineral
FormulaNa(Cu,Fe,Zn)2S4 or Na(Cu,Fe,Zn)2S2:204
IMA symbolCvi
Strunz classification2.FB.10
Crystal systemTrigonal
Crystal classSulfide
Identification
Colorbronze when freshly chipped, gradually blackening to sooty
Crystal habitin the form of free grains and small aggregates
CleavagePerfect on {0001}
Fractureirregular to uneven
Mohs scale hardness3
Lustermetallic
Diaphaneityopaque
Density3.94 (calculated)
Pleochroismdistinct, from pale orange to dark gray with a lilac tint.

Chvilevaite (Russian: чвилеваи́т, чвилёваи́т, in its own name) is a rare hydrothermal polymetallic mineral from the class of complex sulfides, forming microscopic grains in related minerals, its composition is a rare combination of alkali (combining lithophile) and chalcophile metals — sodium ferro-sulfide, zinc and copper with the calculation formula Na(Cu,Fe,Zn)2S4, originally published and confirmed as Na(Cu,Fe,Zn)2S2.:204

The new mineral was studied, described and identified in 1985-1986 and named in honor of Tatyana Chvileva, a leading employee of the Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements, a mineralogist at the Mineragraphy Cabinet.:115