Fornacite

Fornacite is a rare lead, copper chromate arsenate hydroxide mineral with formula: Pb₂Cu(CrO₄)(AsO₄)(OH). The phosphate ion is also reported as substituting in the mineral. It forms variably green to yellow, translucent to transparent crystals in the monoclinic - prismatic crystal system. It has a Mohs hardness of 2.3 and a specific gravity of 6.27.

It was first described in 1915 and named for Named for Lucien Lewis Forneau (1867-1930) the governor of the French Congo. Its type locality is in Reneville, Congo Republic.

References

* [http://www.webmineral.com/data/Fornacite.shtml Webmineral data]
* [http://www.mindat.org/min-1583.html Mindat with locations]