Chengdeite is an extremely rare iridium-iron intermetallic mineral discovered in the platinum-bearing chromitite deposits of China. It typically occurs as microscopic inclusions or grains within other platinum-group minerals, requiring electron microprobe analysis for positive identification.
Is this chengdeite?
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 chengdeite with a known reference. Chengdeite sits at Mohs 5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: steel black.
- 5Look at form & habitCrystal system: cubic. Typical habit: nuggets.
Often confused with
Chengdeite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside chengdeite
Minerals reported to co-occur with chengdeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ir₃Fe
- Mohs hardness
- 5
- Density
- 19.3 g/cm³
- Colors
- Steel black
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Nuggets
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Research
- Host rock
- In chromite ores in ultramafic rocks and in placer concentrates derived therefrom
Where rockhounds find chengdeite
Classic worldwide localities
- At the branch of the Luan river (about 200 km NNE of Beijing) in Chengde County, Peoples Republic of China (type locality)
Field-hunting tip
Where it forms: In chromite ores in ultramafic rocks and in placer concentrates derived therefrom. If you start seeing inaglyite, osmiridium, ferrian platinum in float, you are in the right ground. Typical habit: nuggets. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify chengdeite?+
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What rocks look like chengdeite?+
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Find chengdeite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
