Omeiite is an extremely rare osmium arsenide found primarily in platinum-group element bearing deposits. It typically occurs as small, metallic grains, often requiring microscopic study for positive identification due to its similarity to other arsenide minerals.

Hardness

4-5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Omeiite

Hardness: 4-5
Luster: Metallic
Streak: Black
Transparency: Opaque

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Is this omeiite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch omeiite with a known reference. Omeiite sits at Mohs 4-5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Omeiite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Omeiite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: tin-white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: anhedral to subhedral grains.

Often confused with

Omeiite vs. its common look-alikes — and how to tell them apart in the field.

mineral

Löllingite

Mohs 5.5-6

How to tell apart: Streak differs — Omeiite leaves black, Löllingite leaves gray-black.

How to tell apart: Sperrylite is the harder of the two (Mohs 6-7 vs. 4-5).

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Often found alongside omeiite

Minerals reported to co-occur with omeiite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: OsAs₂
Mohs hardness: 4-5
Density: 9.5 g/cm³
Colors: Tin-white
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Anhedral to Subhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Ultramafic Intrusive Complexes
Typical price: $100-500+ for micros and small specimens

Where rockhounds find omeiite

Classic worldwide localities

Emei Mountain, Sichuan Province, China
various platinum-group element deposits

Field-hunting tip

Look in ultramafic intrusive complexes country — that is the host setting where omeiite typically forms. If you start seeing platinum, irarsite, chalcopyrite in float, you are in the right ground. Field specimens usually show a anhedral to subhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify omeiite?+

Mohs hardness is 4-5. It typically shows a metallic luster. The streak is black. Common colors include tin-white.

Where is omeiite found?+

Notable localities include Emei Mountain, Sichuan Province, China; various platinum-group element deposits.

How much is omeiite worth?+

Typical asking prices fall in the range of $100-500+ for micros and small specimens. Quality, size, and provenance can move individual specimens well outside that range.

Is omeiite safe to handle?+

It contains toxic constituents. Omeiite contains arsenic; handle with care and wash hands thoroughly after handling specimen to avoid ingestion or inhalation of dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like omeiite?+

Omeiite is most often confused with Löllingite, Sperrylite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with omeiite?+

Omeiite commonly co-occurs with Platinum, Irarsite, Chalcopyrite, Bornite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does omeiite form in?+

Omeiite typically forms in ultramafic intrusive complexes. Working float back to the host body is the standard way to chase a fresh occurrence.

What is omeiite used for?+

Omeiite is used in collector.

Find omeiite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.