Miassite is a very rare rhodium sulfide mineral first discovered in the Ural Mountains. It is typically found as microscopic inclusions within platinum group mineral assemblages in ultramafic rocks, making it a highly sought-after specimen for advanced mineral collectors.
Is this miassite?
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 miassite with a known reference. Miassite 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: gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: inclusions.
Often confused with
Miassite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Miassite is noticeably harder (Mohs 5.5-6 vs. 2.5-2.75); streak differs, so Miassite leaves black, Galena leaves lead-gray.
How to tell apart: Miassite is noticeably harder (Mohs 5.5-6 vs. 3.5-4); streak differs, so Miassite leaves black, Pentlandite leaves pale bronze-brown.
Often found alongside miassite
Minerals reported to co-occur with miassite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Rh₁₇S₁₅
- Mohs hardness
- 5.5-6
- Density
- 7.42 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Inclusions
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In heavy-mineral concentrates from fluvial placer deposits derived from ophiolites or layered mafic intrusions
Where rockhounds find miassite
Classic worldwide localities
- Upper part of the Miass River, near Zlatoust, southern Urals, Russia (type locality)
- Burwash Creek, a tributary of the Kluane River, southeastern Yukon Territory, Canada
- Anabar Basin placer, northeastern Siberian Platform, Russia
- Moopetsi River and its subsidiary creeks, farm Maandagshoek, eastern Bushveld, South Africa
Field-hunting tip
Where it forms: In heavy-mineral concentrates from fluvial placer deposits derived from ophiolites or layered mafic intrusions. If you start seeing isoferroplatinum, cuprorhodsite, bowieite in float, you are in the right ground. Typical habit: inclusions. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify miassite?+
Where is miassite found?+
What rocks look like miassite?+
What minerals are found with miassite?+
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Find miassite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
