Crocoite is mainly used as a mineral specimen. It used to be
used as a minor ore of chromium, but it is now too rare to be used
for that.It is on wikipedia too
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Chromium was discovered in the mineral crocoite (PbCrO4) - Ural
Mountains (Russia).
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Chrome isn't a rock.
Chromium is mostly found in the form of the minerals chromite
(an oxide of iron and chromium) and crocoite (lead chromate).
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Rubellite, Almandine, Carnelian, Ruby Jack(Red variety of
Sphalerite), Red Beryl, PYROPE, CROCOITE, RED AVENTURINE, RED
JASPER, RHODONITE