What is "bayleyite"

n. (context mineral English) A monoclinic-prismatic mineral containing carbon, hydrogen, magnesium, oxygen, and uranium.

Bayleyite is an uranium carbonate mineral with the chemical formula: Mg(UO)(CO)·18(HO). It is a secondary mineral which contains magnesium, uranium and carbon. It is a bright yellow color. Its crystal habit is acicular but is more commonly found as crusts on uranium bearing ores. It has a Mohs hardness of about 2-2.5.