Irarsite is a very rare platinum-group mineral typically found in heavy mineral concentrates of alluvial deposits or ultramafic complexes. It is a metallic mineral identified by its distinct silver-white color and high density, often requiring X-ray diffraction or microprobe analysis to distinguish it from other rare platinum-group species.
Is this irarsite?
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 irarsite with a known reference. Irarsite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Irarsite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Irarsite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: silver-white, steel-gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: small euhedral crystals, granular, massive.
Often confused with
Irarsite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Irarsite leaves black, Cobaltite leaves greyish-black.
How to tell apart: Streak differs — Irarsite leaves black, Gersdorffite leaves grayish-black.
How to tell apart: Streak differs — Irarsite leaves black, Hollingworthite leaves grayish-black.
Often found alongside irarsite
Minerals reported to co-occur with irarsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- IrAsS
- Mohs hardness
- 6
- Density
- 9.5-9.8 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Small Euhedral Crystals, Granular, Massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Ultramafic Igneous Rocks and Placers
- Typical price
- $50-300 per small specimen
Where rockhounds find irarsite
Classic worldwide localities
- Yubdo, Ethiopia
- Witwatersrand, South Africa
- Kondyor Massif, Russia
- Sudbury, Canada
Field-hunting tip
Look in ultramafic igneous rocks and placers country — that is the host setting where irarsite typically forms. If you start seeing platinum, osmium, rutheniridosmine in float, you are in the right ground. Field specimens usually show a small euhedral crystals, granular, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify irarsite?+
Where is irarsite found?+
How much is irarsite worth?+
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What rocks look like irarsite?+
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Find irarsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
