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. Rutheniridosmine leaves a gray streak.
- 3Read the lusterHold the specimen under a strong light. Rutheniridosmine typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: silver-white, light steel-gray.
- 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 — Rutheniridosmine leaves gray, Platinum leaves steel-gray.

How to tell apart: Streak differs — 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
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Small Flattened Hexagonal Grains, Scales, Or Nuggets
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Ultramafic Igneous Rocks, Placer Deposits
- Typical price
- $50-500 per specimen depending on size and provenance
Where rockhounds find rutheniridosmine
Classic worldwide localities
- Bushveld Complex, South Africa
- Ural Mountains, Russia
- Goodnews Bay, Alaska
- Tasmania, Australia
Field-hunting tip
Look in ultramafic igneous rocks, placer deposits country — that is the host setting where rutheniridosmine typically forms. If you start seeing platinum, chromite, magnetite in float, you are in the right ground. Field specimens usually show a small flattened hexagonal grains, scales, or nuggets habit, so train your eye for that shape before scanning the outcrop.



