Erythrite

A hydrated cobalt arsenate mineral

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Etymology

The name "erythrite" is derived from the Greek word "erythros," meaning red, in reference to its distinctive color.

Chemical composition

Erythrite is a secondary hydrated cobalt arsenate mineral with the chemical formula Co_(AsO_)_·8H_O. It forms as a result of the oxidation of primary cobalt minerals.

Physical properties

Erythrite typically forms in the monoclinic crystal system and is known for its striking pink to red color, which is due to the presence of cobalt. It has a Mohs hardness of 1.5 to 2.5, making it relatively soft. The mineral exhibits a pearly to vitreous luster and has a specific gravity of approximately 3.1.

Occurrence

Erythrite is commonly found in the oxidized zones of cobalt and nickel deposits. It is often associated with other secondary minerals such as annabergite, scorodite, and cobaltite. Notable localities include the Bou Azzer District in Morocco, the Cobalt District in Ontario, Canada, and the Blackbird Mine in Idaho, USA.

Uses

While erythrite itself is not a major ore of cobalt, it serves as an important indicator mineral for the presence of cobalt deposits. Its vibrant color also makes it a popular specimen among mineral collectors.

Gallery

Erythrite specimen showing its characteristic pink color.

Related pages

• Cobaltite
• Annabergite
• Scorodite
• Mineral collecting