Formula: Bi2MoO6
Anhydrous molybdate, koechlinite group
Crystal System: Orthorhombic
Specific gravity: 8.26 calculated
Streak: Pale greenish yellow
Colour: Greenish yellow, white to light grey, greenish yellow in transmitted light
Solubility: Readily soluble in hydrochloric acid, less so in nitric acid

Hydrothermal environments

Koechlinite occurs as a rare alteration product in the oxidation zone of bismuth-molybdenum deposits (HOM).


At the Little Bygoo group mines, Ardlethan, Bourke county, New South Wales, Australia, koechlinite occurs with bismoclite (AM 28.536-540, Dana).

At the Old 25 Pipe, Kingsgate, Gough county, New South Wales, Australia, koechlinite occurs as secondary, massive material between blades of molybdenite, and occasionally as fibres, probably pseudomorphing bismuthinite; it is frequently associated with bismite and bismutite (AJM 10-1.9-10).

At the Dunallen Gold Mine, Coolgardie, Coolgardie Shire, Western Australia, koechlinite occurs as an alteration product of tetradymite (Dana).

At the type locality, the Daniel mine, Neustädtel, Schneeberg, Erzgebirgskreis, Saxony, Germany, koechlinite occurs in cavities in vein material composed of quartz, bismuth and skutterudite (Webmin, Dana, HOM).

At the Torgovskoe Uranium deposit, Torgo River Basin, Chara and Tokko Rivers Confluence, Aldan Shield, Sakha Republic, Eastern-Siberian Region, Russia, koechlinite is associated with molybdenite, bismuthinite, aikinite, bismite, wulfenite and quartz (HOM).

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