Kolovratite

kolovratite

vesignieite

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Formula: (Ni,Zn)x(VO4).nH2O
Valence: (Ni2+,Zn2+)xV5+O4.nH2O surely x should be 1.5, or V5+ should have subscript (1.6-0.4x)
Hydrated vanadate of nickel and zinc
Hardness: 2 to 3
Streak: Pale yellow
Colour: Citrine-yellow, greenish yellow
Slightly RADIOACTIVE
Environments

Metamorphic environments

Kolovratite is a questionable mineral species (IMA). It occurs as fibrous and felted aggregates, in botryoidal crusts and thin encrustations (HOM)

Localities

At the type locality, Kara-Chagyr Mountain, Kadamjay District, Batken Region, Kyrgyzstan, kolovratite has been reported in quartz schists and carbonaceous slates (HOM).
In 1951 kolovratite was also reported to be widely distributed as yellow to greenish yellow encrustations and botryoidal crusts in quartz schists and carbonaceous slates at Uch-Kurgan, Ferghana Valley, Osh Region, Kyrgyzstan. The lack of descriptive data has long resulted in the mineral being regarded as a doubtful species.
In 1955 an investigation of copper and vanadium arsenates from the Agalyk U-V deposit, Kara-Tyube Mtn, Samarqand, Uzbekistan, a specimen purported to be kolovratite was found to be identical to vésigniéite, leading to a suggestion that kolovratite should be discredited.
In 1962, however, Two specimens of kolovratite from the type locality were examined. The X-ray powder patterns of the two kolovratites are identical, but differ markedly from the pattern of vésigniéite. Small samples of greenish crusts were scraped from each of the samples for testing. The close similarity in the ratios of the major constituents and the identical powder diffraction patterns obtained from the two specimens suggests that a single nickel - zinc - vanadium mineral is present in both specimens (CM 7.311–314).
The jury is still out!

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