Sperrylite is a rare and dense platinum arsenide mineral primarily found in magmatic nickel-copper deposits. It typically forms metallic, brilliant silver-white crystals that look superficially similar to pyrite but are significantly heavier. Collectors prize it as the most important mineral source of platinum.
Is this sperrylite?
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 sperrylite with a known reference. Sperrylite sits at Mohs 6-7 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Sperrylite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Sperrylite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: tin-white, silver-white, lead-gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: often as cubic, octahedral, or dodecahedral crystals, sometimes massive or granular.
Often confused with
Sperrylite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Sperrylite leaves black, Pyrite leaves greenish-black to brownish-black.
How to tell apart: Streak differs — Sperrylite leaves black, Cobaltite leaves greyish-black.
Often found alongside sperrylite
Minerals reported to co-occur with sperrylite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PtAs₂
- Mohs hardness
- 6-7
- Density
- 10.6 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Often as Cubic, Octahedral, Or Dodecahedral Crystals, Sometimes Massive or Granular
- Cleavage
- Indistinct
- Rarity
- Rare
- Uses
- Collector, Ore of Platinum
- Host rock
- Magmatic Sulfide Deposits, Nickel-copper Ore Bodies
- Typical price
- $50-500 thumbnail, $500-2000+ cabinet specimen
Where rockhounds find sperrylite
Classic worldwide localities
- Sudbury Basin, Ontario, Canada
- Bushveld Complex, South Africa
- Norilsk, Russia
- Stillwater Complex, Montana, USA
Field-hunting tip
Look in magmatic sulfide deposits, nickel-copper ore bodies country — that is the host setting where sperrylite typically forms. If you start seeing chalcopyrite, pentlandite, pyrrhotite in float, you are in the right ground. Field specimens usually show a often as cubic, octahedral, or dodecahedral crystals, sometimes massive or granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify sperrylite?+
Where is sperrylite found?+
How much is sperrylite worth?+
Is sperrylite safe to handle?+
What rocks look like sperrylite?+
What minerals are found with sperrylite?+
What kind of rock does sperrylite form in?+
What is sperrylite used for?+
Find sperrylite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
