mineral

Proustite

Proustite (Ag3AsS3)

Mohs hardness: 2-2.5; Color: Scarlet-vermilion to deep ruby-red; Luster: Adamantine to submetallic; Crystal structure: Trigonal; Specific gravity: 5.57-5.64; Streak: Red.

Hardness: 2-2
Color: Scarlet-vermilion to deep ruby-red
Luster: Adamantine to submetallic

Identified June 7, 2026More mineral →

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Physical properties

Mohs hardness: 2-2.5; Color: Scarlet-vermilion to deep ruby-red; Luster: Adamantine to submetallic; Crystal structure: Trigonal; Specific gravity: 5.57-5.64; Streak: Red.

Formation & geological history

Formed in hydrothermal veins as a secondary mineral in the oxidation zone of silver deposits or as a primary late-stage mineral. Often found with other silver sulfosalts like pyrargyrite.

Uses & applications

Historically used as an ore of silver; today primarily valued by mineral collectors for its vibrant color and crystal forms.

Geological facts

Commonly known as 'ruby silver' or 'light red silver ore' due to its striking color. It is photosensitive and can darken to a dull metallic or black color if exposed to light for prolonged periods.

Field identification & locations

Identified by its distinctive ruby color, deep red streak, and high luster. Commonly found in areas like the Erzgebirge in Germany, Mexico, and Chile. Collectors must store it in dark containers to preserve color.