crocoite

crocoite, mineral consisting of lead chromate, PbCrO₄, that is identical in composition to chrome yellow, the artificial product used in paint. The element chromium was discovered in this mineral in 1797. Crocoite occurs as long, well-developed, prismatic crystals; the most beautiful specimens are from Dundas, Tasmania. Other localities include the Urals, Brazil, and the southwestern United States. Crocoite has a bright hyacinth-red to orange colour and an adamantine to vitreous lustre that dulls on exposure to sunlight.