Petrovskaite is a very rare silver gold sulfide mineral found in epithermal ore deposits. It typically occurs as microscopic anhedral grains intergrown with other telluride minerals and native gold.
Is this petrovskaite?
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 petrovskaite with a known reference. Petrovskaite sits at Mohs 2-2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: dark gray.
- 3Read the lusterHold the specimen under a strong light. Luster: dull metallic.
- 4Match the color rangeCompare against the expected color range: lead gray, dark grayish black, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: microscopic crystals.
Often confused with
Petrovskaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Petrovskaite leaves dark gray, Acanthite leaves black; luster reads dull metallic on Petrovskaite and metallic on Acanthite.
How to tell apart: Streak differs, so Petrovskaite leaves dark gray, Petzite leaves grayish black; luster reads dull metallic on Petrovskaite and metallic on Petzite.
How to tell apart: Streak differs, so Petrovskaite leaves dark gray, Hessite leaves light gray; luster reads dull metallic on Petrovskaite and metallic on Hessite.
Often found alongside petrovskaite
Minerals reported to co-occur with petrovskaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AgAuS
- Mohs hardness
- 2-2.5
- Density
- 9.5 g/cm³
- Streak
- Dark gray
- Luster
- Dull metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Microscopic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- At a depth of about 60–65 m in a gold deposit
Where rockhounds find petrovskaite
Classic worldwide localities
- Maikain gold deposit, Pavlodar district, northeast Kazakhstan (type locality)
Field-hunting tip
Where it forms: At a depth of about 60–65 m in a gold deposit. If you start seeing gold, chlorargyrite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find petrovskaite on the map
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