Chvilevaite (Russian: чвилеваи́т, чвилёваи́т, in its own name)[5] 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,[1] originally published and confirmed as Na(Cu,Fe,Zn)2S2.
[2][3]: 204 The new mineral was studied, described and identified in 1985-1986 and named in honor of Tatyana Chvileva,[6] a leading employee of the Institute of Mineralogy, Geochemistry and Crystal Chemistry of Rare Elements, a mineralogist at the Mineragraphy Cabinet.
[7]: 115 Initially, a new mineral of the approximate composition Na(Cu,Fe,Zn)2S2[2] was discovered as very small grains of inclusion in archival samples of sphalerite from the Akatuy lead-zinc deposit (Alexandrovo-Zavodsky district of the Trans-Baikal Territory), obtained by the microscopy laboratory of the IMGRE from the funds of the Mineralogical Museum of the Academy of Sciences USSR.
It was named in honor of the authoritative mineralogist and mineralographer Tatyana Chvileva, whose scientific portfolio at that time already included four new discovered mineral species.
[8]: 90 Taking into account the constantly occurring fluctuations in the content of all elements in the mineral, in 1988 the general formula of chvilevaite was presented in proportional form, as (Na2,00Ca0,03)2,03(Cu2,56FeO,88Zn0,43As0,03Mn0,005)3,90S4,06.
In particular, murunskite, found on Mount Koashva in pegmatites of the same type as the new mineral orikite discovered in the Khibiny Mountains in 2007, has a similar crystal structure.
However, a detailed X-ray study and modeling of the powder pattern of the found orikite showed that this mineral and chvilevaite are most likely not direct structural analogues.
[3] Thus, typical associations for chvilevaite are minerals of hydrothermal veins: sphalerite, covellite, chalcocite, galena, pyrite, boulangerite, arsenopyrite, carbonates and quartz.
To a depth of 40–80 meters, the ores are highly oxidized and are represented by a mixture of limonite, cerussite, smithsonite and the remains of undecomposed galena with quartz.