Native osmium is an extremely dense, metallic mineral belonging to the platinum group. It is most commonly found as small, heavy, chemically resistant grains or flattened hexagonal crystals in alluvial placer deposits derived from ultramafic rocks.
Is this native osmium?
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 native osmium with a known reference. Native Osmium 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: steel gray.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: granular.
Often confused with
Native Osmium vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside native osmium
Minerals reported to co-occur with native osmium. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Os
- Mohs hardness
- 6-7
- Density
- 22.48 g/cm³
- Colors
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Granular
- Cleavage
- Perfect on {0001}
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- With other platinum-group elements and alloys, in ultramafic rocks and placers derived therefrom
Where rockhounds find native osmium
Classic worldwide localities
- Fox Gulch and the Salmon River, Goodnews Bay, Alaska, USA
- Ruby Creek, Atlin, British Columbia, Canada
- Rio Pilpe, Colombia
- Santiago River placers, Esmeraldas Province, Ecuador
- Gusevogorskii pluton, and the Kytlym and Uktus complexes, Ural Mountains, Russia
- Neozhidannyy Creek placers, Tuva, Russia
Field-hunting tip
Where it forms: With other platinum-group elements and alloys, in ultramafic rocks and placers derived therefrom. If you start seeing rutheniridosmine, iridosmine, osmiridium in float, you are in the right ground. Typical habit: granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify native osmium?+
Where is native osmium found?+
Is native osmium safe to handle?+
What rocks look like native osmium?+
What minerals are found with native osmium?+
What kind of rock does native osmium form in?+
What is native osmium used for?+
Find native osmium on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
