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, 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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