Kosmochlor is a rare sodium-chromium pyroxene often found as an inclusion in iron meteorites or within deep-seated metamorphic rocks. It is highly valued by collectors for its intense, vivid emerald-green color, which is caused by its high chromium content. Identification in the field is difficult due to its visual similarity to jadeite and other pyroxenes, often requiring analytical confirmation.
Is this kosmochlor?
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 kosmochlor with a known reference. Kosmochlor sits at Mohs 6-6.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Kosmochlor leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Kosmochlor typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: emerald-green, dark green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, massive, or as granular aggregates.
Often confused with
Kosmochlor vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside kosmochlor
Minerals reported to co-occur with kosmochlor. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCrSi₂O₆
- Mohs hardness
- 6-6.5
- Density
- 3.59 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Massive, Or as Granular Aggregates
- Cleavage
- Good On {110}
- Rarity
- Rare
- Uses
- Collector, Research
- Host rock
- Iron Meteorites and Serpentinized Peridotites
- Typical price
- $50-500 depending on specimen size and provenance
Where rockhounds find kosmochlor
Classic worldwide localities
- Toluca, Mexico
- Myanmar
- Russia
- California, USA
Field-hunting tip
Look in iron meteorites and serpentinized peridotites country — that is the host setting where kosmochlor typically forms. If you start seeing chromite, olivine, enstatite in float, you are in the right ground. Field specimens usually show a fibrous, massive, or as granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kosmochlor?+
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How much is kosmochlor worth?+
What rocks look like kosmochlor?+
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Find kosmochlor on the map
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