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demesmaekerite

n. (context mineral English) A triclinic-pinacoidal mineral containing copper, hydrogen, lead, oxygen, selenium, and uranium.

Wikipedia
Demesmaekerite

Demesmaekerite is an uranium mineral with the chemical formula: PbCu(UO)(SeO)(OH)•2HO.

It is named after the Belgian mineralogist, who worked at the Musonoi Mine, Gaston Demesmaeker (born 1911). It is a secondary mineral which contains lead, copper and (the rarer in minerals) selenium, it is a bottle green to brown/yellow colour, its crystal habit changes from one form to another form depending on where it is found. It has a Mohs hardness of about 2-3.

It can be found alongside other very rare selenium-bearing uranium ores, such as haynesite, guilleminite, marthozite and piretite.