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 4-5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Yarlongite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Yarlongite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: steel-gray.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: grains.
Often confused with
Yarlongite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Yarlongite leaves black, Isoferroplatinum leaves grayish-black.
How to tell apart: Streak differs, so Yarlongite leaves black, Chromite leaves dark brown; luster reads metallic on Yarlongite and submetallic on Chromite.
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
- 4-5
- Density
- 7.19 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Grains
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Podiform Chromitite in Ophiolitic Peridotite
Where rockhounds find yarlongite
Classic worldwide localities
- Luobusa Ophiolite, Tibet, China
Field-hunting tip
Look in podiform chromitite in ophiolitic peridotite country, the host setting where yarlongite typically forms. If you start seeing chromite, diamond, moissanite in float, you are in the right ground. Field specimens usually show a grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify yarlongite?+
Where is yarlongite found?+
What rocks look like yarlongite?+
What minerals are found with yarlongite?+
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Find yarlongite on the map
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