Cuproauride is a rare intermetallic mineral composed of copper and gold. It typically occurs as microscopic grains within gold-bearing veins or volcanic environments and is highly prized by collectors for its unique chemical composition.

Hardness

2.5-3

Mohs

Luster

Metallic

Streak

Yellow

Transparency

Opaque

mineralrareGold Group family

Cuproauride

Hardness: 2.5-3
Luster: Metallic
Streak: Yellow
Transparency: Opaque

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Is this cuproauride?

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 cuproauride with a known reference. Cuproauride sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: yellow.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: yellow, gold-yellow.
5
Look at form & habit
Crystal system: cubic. Typical habit: anhedral grains, massive, interstitial fillings.

Often confused with

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

How to tell apart: Streak differs, so Cuproauride leaves yellow, Copper leaves rose.

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Often found alongside cuproauride

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

All properties

Chemical formula: Cu₃Au
Mohs hardness: 2.5-3
Density: 15.0-16.0 g/cm³
Colors: YellowGold-yellow
Streak: Yellow
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral grains, massive, interstitial fillings
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific research
Host rock: hydrothermal veins, volcanic exhalations

Where rockhounds find cuproauride

Classic worldwide localities

Hope's Nose, Torquay, UK
Kudryavyi Volcano, Kuril Islands, Russia
Komsomolskoye gold deposit, Kazakhstan

Field-hunting tip

Where it forms: hydrothermal veins, volcanic exhalations. If you start seeing gold, hematite, cuprite in float, you are in the right ground. Typical habit: anhedral grains, massive, interstitial fillings. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify cuproauride?+

Mohs hardness is 2.5-3. Luster: metallic. The streak is yellow. Common colors include yellow, gold-yellow.

Where is cuproauride found?+

Notable localities include Hope's Nose, Torquay, UK; Kudryavyi Volcano, Kuril Islands, Russia; Komsomolskoye gold deposit, Kazakhstan.

Is cuproauride safe to handle?+

Cuproauride contains copper. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like cuproauride?+

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

What minerals are found with cuproauride?+

Cuproauride commonly co-occurs with gold, hematite, cuprite, tenorite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does cuproauride form in?+

Where it forms: hydrothermal veins, volcanic exhalations. Working float back to the host body is the standard way to chase a fresh occurrence.

What is cuproauride used for?+

Cuproauride is used in collector, scientific research.

Find cuproauride on the map

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