Cuproiridsite is an extremely rare platinum group mineral primarily found as microscopic inclusions within chromite deposits. Collectors typically seek it out as part of comprehensive platinum-group element suites found in layered ultramafic complexes. Due to its rarity and typical association with other complex metallic ores, it is almost exclusively found in professional scientific or high-end mineral collections.

Hardness

5-6

Mohs

Luster

Metallic

Transparency

Opaque

mineralrareSpinel Group family

Cuproiridsite

Hardness: 5-6
Luster: Metallic
Transparency: Opaque

Is this cuproiridsite?

4-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 cuproiridsite with a known reference. Cuproiridsite sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
2
Read the luster
Hold the specimen under a strong light. Luster: metallic.
3
Match the color range
Compare against the expected color range: iron black, black.
4
Look at form & habit
Crystal system: cubic. Typical habit: anhedral to euhedral grains, inclusions in chromite.

Often confused with

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

How to tell apart: Laurite is the harder of the two (Mohs 7.5 vs. 5-6).

Often found alongside cuproiridsite

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

All properties

Chemical formula: CuIr₂S₄
Mohs hardness: 5-6
Density: 7.24 g/cm³
Colors: Iron black Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Anhedral to euhedral grains, inclusions in chromite
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific research
Host rock: In alluvial deposits

Where rockhounds find cuproiridsite

Classic worldwide localities

Goodnews Bay, Alaska, USA
Kondor (type locality) and Chad massifs, Khabarovsk Territory, Russia
Inagli, Aldan Shield, Russia
Mt. Filipp, Kamchatka, Russia
Ray-Iz ophiolite complex, Polar Ural Mountains, Russia
Chromwerk, Kraubath massif, Styria, Austria

Field-hunting tip

Where it forms: In alluvial deposits. If you start seeing isoferroplatinum, cuprorhodsite, malanite in float, you are in the right ground. Typical habit: anhedral to euhedral grains, inclusions in chromite. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify cuproiridsite?+

Mohs hardness is 5-6. Luster: metallic. Common colors include iron black, black.

Where is cuproiridsite found?+

Notable localities include Goodnews Bay, Alaska, USA; Kondor (type locality) and Chad massifs, Khabarovsk Territory, Russia; Inagli, Aldan Shield, Russia; Mt. Filipp, Kamchatka, Russia; Ray-Iz ophiolite complex, Polar Ural Mountains, Russia.

Is cuproiridsite safe to handle?+

Cuproiridsite 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 cuproiridsite?+

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

What minerals are found with cuproiridsite?+

Cuproiridsite commonly co-occurs with Isoferroplatinum, Cuprorhodsite, Malanite, Osmium, Iridosmine, Platinum. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does cuproiridsite form in?+

Where it forms: In alluvial deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is cuproiridsite used for?+

Cuproiridsite is used in collector, scientific research.

Find cuproiridsite on the map

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