Phoenicochroite

phoenicochroite

hemihedrite

vauquelinite

crocoite

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Formula: Pb2(CrO4)
Chromate
Crystal System: Monoclinic
Specific gravity: 7.01 measured, 7.075 calculated
Hardness: 2½
Streak: Brick red
Colour: Dark red
Solubility: Soluble in hydrochloric acid with separation of lead chloride
Environments:

Hydrothermal environments

Phoenicochroite is a rare secondary mineral in the oxidised zone of chromium-bearing hydrothermal lead deposits, associated with crocoite, vauquelinite, fornacite, hemihedrite, iranite, pyromorphite, mimetite, cerussite, leadhillite, galena, calcite, fluorite and quartz (AM55.784-792).
Phoenicochroite superficially alters to crocoite which is then replaced by cerussite, mimetite and vauquelinite (AM55.784-792).

At the type locality, the Berezovsk Mines, Ural mountains, Russia, phoenicochroite is associated with vauquelinite, pyromorphite, galena, crocoite (Mindat) and anglesite (Dana).

At various localities in Arizona, USA, phoenicochroite occurs with mimetite, willemite, hemihedrite and vauquelinite (Dana).

At the Potter-Cramer mine, Vulture Mining District, Maricopa county, Arizona, USA, phoenicochroite is rare; it and hemihedrite were the first chromates to form in the oxide assemblage at the mine (R&M 96.1.33).

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