mineral

Erythrite

Erythrite (Cobalt Bloom) - Co3(AsO4)2·8H2O

Hardness: 1.5-2.5; Color: Crimson, pink, rose-red; Luster: Adamantine to pearly; Crystal structure: Monoclinic; Cleavage: Perfect; Specific Gravity: 3.06

Hardness: 1
Color: Crimson, pink, rose-red
Luster: Adamantine to pearly

Identified March 30, 2026More mineral →

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Physical properties

Hardness: 1.5-2.5; Color: Crimson, pink, rose-red; Luster: Adamantine to pearly; Crystal structure: Monoclinic; Cleavage: Perfect; Specific Gravity: 3.06

Formation & geological history

A secondary mineral formed through the oxidation of cobalt-rich sulfides and sulfarsenides (like cobaltite) in weathered hydrothermal deposits.

Uses & applications

A major geological indicator for prospectors seeking cobalt and silver; also a prized mineral specimen for collectors due to its vibrant color.

Geological facts

Historically known as 'Cobalt Bloom' by miners because its presence often signaled the proximity of valuable silver and cobalt ores; its name is derived from the Greek word 'erythros', meaning red.

Field identification & locations

Identify by its distinctive magenta/pink color and its frequent association with other cobalt minerals. Commonly found in Morocco (Bou Azzer), Germany (Saxony), and Canada (Ontario).

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