Minerals identify

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Acanthite

Sulfide mineral

Acanthite is a form of silver sulfide with the chemical formula Ag2S. It crystallizes in the monoclinic system and is the stable form of silver sulfide below 173 °C (343 °F). Argentite is the stable form above that temperature. As argentite cools below that temperature its cubic form is distorted to the monoclinic form of acanthite. Below 173 °C acanthite forms directly. Acanthite is the only stable form in normal air temperature.

Identification

Color of mineral

Iron
Black

Mohs scale ( mineral hardness )

2.0

Luster ( interacts light )

Metallic

Crystal ( diaphaneity )

Monoclinic