Changchengite is an extremely rare iridium bismuth telluride mineral first discovered in the Changcheng gold mine in China. It typically occurs as minute, metallic grey grains embedded within massive sulfide ore, requiring advanced mineralogical analysis for identification.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareSulfosalt family

Changchengite

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

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Is this changchengite?

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

Often confused with

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

mineral

Froodite

Mohs 2.5

How to tell apart: Changchengite is noticeably harder (Mohs 3.5 vs. 2.5).

How to tell apart: Changchengite is noticeably harder (Mohs 3.5 vs. 2.5).

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Often found alongside changchengite

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

All properties

Chemical formula: IrBiTe
Mohs hardness: 3.5
Density: 9.2 g/cm³
Colors: Gray White
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $500+ per specimen

Where rockhounds find changchengite

Classic worldwide localities

Changcheng mine, Hebei Province, China

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where changchengite typically forms. If you start seeing chalcopyrite, pyrite, galena 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 changchengite?+

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

Where is changchengite found?+

Notable localities include Changcheng mine, Hebei Province, China.

How much is changchengite worth?+

Typical asking prices fall in the range of $500+ per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is changchengite safe to handle?+

It contains toxic constituents. Contains tellurium and bismuth; avoid inhaling dust or ingesting. Handle with care and wash hands thoroughly after contact. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like changchengite?+

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

What minerals are found with changchengite?+

Changchengite commonly co-occurs with Chalcopyrite, Pyrite, Galena, Sphalerite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does changchengite form in?+

Changchengite typically forms in hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is changchengite used for?+

Changchengite is used in collector.

Find changchengite on the map

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