Petrukite is a rare copper-iron-zinc-tin sulfide mineral that occurs primarily within complex hydrothermal sulfide deposits. It is typically found in massive, granular forms and is often visually indistinguishable from other dark-colored sulfides without sophisticated analytical techniques like X-ray diffraction or electron microprobe analysis.
Is this petrukite?
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 petrukite with a known reference. Petrukite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Petrukite leaves a brown streak.
- 3Read the lusterHold the specimen under a strong light. Petrukite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: dark brown, black.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: massive, anhedral grains.
Often confused with
Petrukite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Petrukite leaves brown, Sphalerite leaves white to yellow-brown; luster reads metallic on Petrukite and resinous to submetallic on Sphalerite.
How to tell apart: Streak differs, so Petrukite leaves brown, Wurtzite leaves brownish-yellow to light brown; luster reads metallic on Petrukite and resinous on Wurtzite.
How to tell apart: Streak differs, so Petrukite leaves brown, Stannite leaves black.
Often found alongside petrukite
Minerals reported to co-occur with petrukite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Cu,Fe,Zn,Ag)₄SnS₆
- Mohs hardness
- 4
- Density
- 4.26 g/cm³
- Colors
- Streak
- Brown
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Massive, Anhedral Grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Sulfide Veins
- Typical price
- $50-300 per specimen
Where rockhounds find petrukite
Classic worldwide localities
- Ikuno Mine, Japan
- Akenobe Mine, Japan
Field-hunting tip
Look in hydrothermal sulfide veins country, the host setting where petrukite typically forms. If you start seeing sphalerite, chalcopyrite, stannite in float, you are in the right ground. Field specimens usually show a massive, anhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find petrukite on the map
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