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.

Hardness

3.5-4

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrarenull family

Miassite

Hardness: 3.5-4
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this miassite?

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 miassite with a known reference. Miassite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Miassite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Miassite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: silver-white, gray.
5
Look at form & habit
Crystal system: cubic. Typical habit: anhedral grains.

Often confused with

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

mineral

Galena

Mohs 2.5

How to tell apart: Miassite is noticeably harder (Mohs 3.5-4 vs. 2.5); streak differs — Miassite leaves black, Galena leaves lead-gray.

How to tell apart: Streak differs — Miassite leaves black, Pentlandite leaves light bronze-brown.

Compare →

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: 3.5-4
Density: 9.35 g/cm³
Colors: Silver-white Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Ultramafic Igneous Rocks
Typical price: $100-500 for micro-mounts

Where rockhounds find miassite

Classic worldwide localities

Miass, Ural Mountains, Russia
Konder Massif, Russia
Stillwater Complex, USA

Field-hunting tip

Look in ultramafic igneous rocks country — that is the host setting where miassite typically forms. If you start seeing platinum group minerals, chromite, magnetite in float, you are in the right ground. Field specimens usually show a anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify miassite?+

Mohs hardness is 3.5-4. It typically shows a metallic luster. The streak is black. Common colors include silver-white, gray.

Where is miassite found?+

Notable localities include Miass, Ural Mountains, Russia; Konder Massif, Russia; Stillwater Complex, USA.

How much is miassite worth?+

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

What rocks look like miassite?+

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

What minerals are found with miassite?+

Miassite commonly co-occurs with Platinum group minerals, Chromite, Magnetite, Olivine. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does miassite form in?+

Miassite typically forms in ultramafic igneous rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is miassite used for?+

Miassite is used in collector.

Find miassite on the map

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