Rock Identifier
Crocoite (Lead chromate (PbCrO4)) — mineral
mineral

Crocoite

Lead chromate (PbCrO4)

Hardness: 2.5-3.0 Mohs; Color: Bright hyacinth-red to orange-red; Luster: Adamantine to vitreous; Crystal Structure: Monoclinic; Cleavage: Distinct; Specific Gravity: 5.9-6.1

Hardness
2
Color
Bright hyacinth-red to orange-red
Luster
Adamantine to vitreous
Identified More mineral
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Physical properties

Hardness: 2.5-3.0 Mohs; Color: Bright hyacinth-red to orange-red; Luster: Adamantine to vitreous; Crystal Structure: Monoclinic; Cleavage: Distinct; Specific Gravity: 5.9-6.1

Formation & geological history

An oxidation zone mineral typically found in the weathered parts of lead ore deposits, particularly where chromium-containing rocks are present. Notable formations occurred during the Tertiary period.

Uses & applications

Primarily a collector's mineral due to its rarity and striking color. Historically used as a source of chromium and pigments, but currently too rare for industrial use.

Geological facts

Crocoite was the mineral in which the element chromium was first discovered by Louis-Nicolas Vauquelin in 1797. The most world-renowned specimens come from the Adelaide Mine in Tasmania, Australia.

Field identification & locations

Identified by its vivid 'traffic-cone' orange color and prismatic crystal habit. It is very fragile and sensitive to light, which can cause the color to darken over time. Often found associated with pyromorphite or limonite.