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. Pyrostilpnite leaves a orange-yellow streak.
- 3Read the lusterHold the specimen under a strong light. Pyrostilpnite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: hyacinth-red, orange-red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy or lath-like crystals, often in radiating clusters.
Often confused with
Pyrostilpnite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Pyrostilpnite leaves orange-yellow, Pyrargyrite leaves red; luster reads adamantine on Pyrostilpnite and metallic to adamantine on Pyrargyrite.
How to tell apart: Streak differs — Pyrostilpnite leaves orange-yellow, Proustite leaves scarlet.
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
- 5.9-6.0 g/cm³
- Colors
- Streak
- Orange-yellow
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy or Lath-like Crystals, Often in Radiating Clusters
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Low-temperature Hydrothermal Silver Veins
- Typical price
- $50-500 thumbnail specimen depending on crystal size and provenance
Where rockhounds find pyrostilpnite
Classic worldwide localities
- Freiberg, Saxony, Germany
- Andreasberg, Harz Mountains, Germany
- Příbram, Czech Republic
- Hiendelaencina, Spain
Field-hunting tip
Look in low-temperature hydrothermal silver veins country — that is the host setting where pyrostilpnite typically forms. If you start seeing pyrargyrite, stephanite, silver in float, you are in the right ground. Field specimens usually show a platy or lath-like crystals, often in radiating clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find pyrostilpnite on the map
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