Crocoite is a fairly rare mineral in many parts of the world, consisting of lead chromate, PbCrO4. The relative rareness comes from the way it forms: it requires an oxidation zone of lead ore bed and presence of what are called ultramafic rocks, which act as a source of chromium. Ultramafic rocks are 90% mafic minerals (dark colored, high magnesium and iron content) – the mantle is composed of such rocks.
Andrei is no scientist, but from an early age, he has been fascinated by science; that's why he went to college, and signed up for Geophysics. Feeling that there's a huge gap between science and average people, he rallied TP, started ZME Science, and gave it a green twist too. 
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Published on Wed, Oct 3, 2012 by Mihai Andrei
Post filled in: Geology, GeoPicture