Insizwaite is a rare platinum-bismuth mineral typically found as microscopic inclusions within copper-nickel sulfide ore bodies. Collectors often identify it via polished sections using reflected light microscopy, as it is rarely found in large, well-formed crystals. It is most commonly sourced from major magmatic sulfide mining districts like Insizwa or Norilsk.
Is this insizwaite?
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 insizwaite with a known reference. Insizwaite sits at Mohs 4-5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Insizwaite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Insizwaite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: white, gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: anhedral grains, inclusions in other sulfides.
Often confused with
Insizwaite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Sperrylite is the harder of the two (Mohs 6-7 vs. 4-5).
How to tell apart: Insizwaite is noticeably harder (Mohs 4-5 vs. 2.5).
How to tell apart: Insizwaite is noticeably harder (Mohs 4-5 vs. 2.5-3).
Often found alongside insizwaite
Minerals reported to co-occur with insizwaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PtBi₂
- Mohs hardness
- 4-5
- Density
- 9.2-9.4 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Anhedral Grains, Inclusions in Other Sulfides
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Magmatic Sulfide Deposits in Layered Mafic Intrusions
- Typical price
- $50-300 per micro-mount or small specimen
Where rockhounds find insizwaite
Classic worldwide localities
- Insizwa, South Africa
- Norilsk, Russia
- Stillwater complex, USA
Field-hunting tip
Look in magmatic sulfide deposits in layered mafic intrusions country — that is the host setting where insizwaite typically forms. If you start seeing pentlandite, chalcopyrite, pyrrhotite in float, you are in the right ground. Field specimens usually show a anhedral grains, inclusions in other sulfides habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find insizwaite on the map
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