Yarlongite is an exceptionally rare chromium-iron-nickel carbide found primarily in the Luobusa ophiolite of Tibet. It typically occurs as microscopic grains within chromite ores and represents a fascinating example of high-pressure minerals formed in the Earth's mantle.
Is this yarlongite?
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 yarlongite with a known reference. Yarlongite sits at Mohs 5.5-6, 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 gray.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: irregular grains.
Often confused with
Yarlongite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside yarlongite
Minerals reported to co-occur with yarlongite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cr₄Fe₄NiC₄
- Mohs hardness
- 5.5-6
- Density
- 7.19 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Irregular grains
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In heavy mineral separates from an ophiolitic podiform chromitite
Where rockhounds find yarlongite
Classic worldwide localities
- Luobasha mine, Qusum County, Shannan Prefecture, Tibet Autonomous Region, People's Republic of China
Field-hunting tip
Where it forms: In heavy mineral separates from an ophiolitic podiform chromitite. If you start seeing cohenite, tongbaite, khamrabaevite in float, you are in the right ground. Typical habit: irregular grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yarlongite?+
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Is yarlongite safe to handle?+
What rocks look like yarlongite?+
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Find yarlongite on the map
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