Pyrostilpnite is a rare silver sulfosalt that forms striking, thin, lath-like crystals with an intense orange-red color. It is a dimorph of pyrargyrite and is best identified by its distinct platy habit and metallic-to-adamantine luster in hydrothermal vein environments.
Is this pyrostilpnite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch pyrostilpnite with a known reference. Pyrostilpnite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow-orange.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: hyacinth red, orange red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular, crystalline.
Often confused with
Pyrostilpnite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside pyrostilpnite
Minerals reported to co-occur with pyrostilpnite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₃SbS₃
- Mohs hardness
- 2
- Density
- 5.94 g/cm³
- Colors
- Hyacinth redOrange red
- Streak
- Yellow-orange
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular, crystalline
- Cleavage
- Perfect on {010}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- In low-temperature hydrothermal veins as a late-stage mineral
Where rockhounds find pyrostilpnite
Classic worldwide localities
- Silver City district, Owyhee Co., Idaho, USA
- Bulldog mine, Creede, Mineral Co., Colorado, USA
- Randsburg, San Bernardino Co., California, USA
- St. Andreasberg, Harz Mountains (type locality), Germany
- Hiendelaencina, Guadalajara Province, Spain
- Příbram and at Třebsko, Czech Republic
Field-hunting tip
Where it forms: In low-temperature hydrothermal veins as a late-stage mineral. If you start seeing pyrargyrite, stephanite, acanthite in float, you are in the right ground. Typical habit: acicular, crystalline. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify pyrostilpnite?+
Where is pyrostilpnite found?+
Is pyrostilpnite safe to handle?+
What rocks look like pyrostilpnite?+
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Find pyrostilpnite on the map
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