Rutheniridosmine is a rare native metal alloy primarily found as small, durable grains in placer deposits derived from ultramafic rocks. Collectors typically seek out its characteristic silvery-white metallic luster and heavy weight, which is significantly denser than most common minerals.
Is this rutheniridosmine?
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 rutheniridosmine with a known reference. Rutheniridosmine sits at Mohs 6-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: small flattened hexagonal grains, scales, or nuggets.
Often confused with
Rutheniridosmine vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Rutheniridosmine is noticeably harder (Mohs 6-7 vs. 4-4.5); streak differs, so Rutheniridosmine leaves gray, Platinum leaves grayish white.
How to tell apart: Streak differs, so Rutheniridosmine leaves gray, Sperrylite leaves black.
Often found alongside rutheniridosmine
Minerals reported to co-occur with rutheniridosmine. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Os,Ir,Ru)
- Mohs hardness
- 6-7
- Density
- 19.0-21.5 g/cm³
- Colors
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Small flattened hexagonal grains, scales, or nuggets
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In placer sands, generally derived from ultramafic rocks
Where rockhounds find rutheniridosmine
Classic worldwide localities
- Zlatoust, Ural Mountains, Russia
- Konder massif, Aldan Shield, Sakha, Russia
- Vourinos, Greece
- Witwatersrand, South Africa
- Heazlewood and Adamsfield districts, Tasmania, Australia
- Ironstone Creek, Parapara, New Zealand
Field-hunting tip
Where it forms: In placer sands, generally derived from ultramafic rocks. If you start seeing sperrylite, hollingworthite, iridarsenite in float, you are in the right ground. Typical habit: small flattened hexagonal grains, scales, or nuggets. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify rutheniridosmine?+
Where is rutheniridosmine found?+
What rocks look like rutheniridosmine?+
What minerals are found with rutheniridosmine?+
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Find rutheniridosmine on the map
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