Pyrargyrite — “dark ruby silver” — is the antimony analogue of proustite. The pair forms the classic “ruby silver” sulfosalts of historic silver mining: pyrargyrite is the more abundant, deeper-red and slightly more stable to light exposure.
Properties
- Formula: Ag3SbS3
- Crystal system: Trigonal
- Hardness: 2.5
- Color: Deep ruby-red to nearly black, translucent in thin splinters
- Streak: Purplish-red
- Luster: Adamantine
- Cleavage: Distinct on {1011}
- Density: 5.8 – 5.9 g/cm³
Occurrence
Type locality: St. Andreasberg (Harz, Germany). Other historic sources: Freiberg (Germany), Příbram (Czech Rep.), Hiendelaencina (Spain), Guanajuato (Mexico). Chinese occurrences are minor.
Identification
Nearly black-red translucent trigonal prisms + adamantine luster + purplish-red streak. Pyrargyrite is darker than proustite (which is brighter scarlet) and slightly more stable to light. The streak color difference is decisive — proustite’s is brick-red, pyrargyrite’s is purplish.
Collector Notes
Příbram and Freiberg pyrargyrite specimens with sharp scalenohedral crystals are historical classics. Light-sensitive but slightly less so than proustite.
Found at these Localities
- Imiter Mine (伊米泰尔银矿)
- Příbram (普日布拉姆银矿)
- Chañarcillo (查尼亚西略)
- Ying Silver Mine (银矿(豫西银多金属矿带))
