Usovite

usovite

thorite

chamosite

calcjarlite

Images

Formula: Ba2CaMgAl2F14
Fluoride, barium-bearing mineral
Crystal System: Monoclinic
Specific gravity: 4.26 calculated
Hardness: 3#189;
Streak: White
Colour: Brown to dark brown, yellow, white, colourless
Luminescence: No fluorescence under UV
Solubility: Dissolves when heated in concentrated hydrochloric, nitric or sulphuric acid
Magnetism: Diamagnetic
Environments

Metamorphic environments

Localities

At the type locality, Fluorite vein, Parvaya Noiba River, Enisei Range, Krasnoyarsk Krai, Russia, usovite occurs intergrown with green and colourless fluorite. It is mainly in irregular grains, 0.5 to 3.0 mm, sometime as indistanct elongated platy forms up to 1.5 x 0.5 cm (AM 52.1582).
It occurs in the fluorite vein in quartz-mica schists, associated with fluorite, calcjarlite, muscovite, thorite, chamosite, zeolites and halloysite (HOM).
Usovite from the Parvaya Noiba River - Image

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