Catamarcaite is a very rare copper-germanium-tungsten sulfide mineral known primarily from the Capillitas mine in Argentina. It typically appears as small, gray metallic grains associated with other rare germanium-bearing sulfides.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Catamarcaite

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

No image

Is this catamarcaite?

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 catamarcaite with a known reference. Catamarcaite 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. Streak: black.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: gray.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: aggregates, granular.

Often confused with

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

mineral

Germanite

Mohs 4

How to tell apart: Streak differs, so Catamarcaite leaves black, Germanite leaves dark gray to black.

How to tell apart: Streak differs, so Catamarcaite leaves black, Renierite leaves blackish gray.

Compare →

Often found alongside catamarcaite

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

All properties

Chemical formula: Cu₆GeWS₈
Mohs hardness: 3.5
Density: 4.892 g/cm³
Colors: Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Aggregates, granular
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In an epithermal bornite-rich ore in a copper, silver, and gold deposit

Where rockhounds find catamarcaite

Classic worldwide localities

Old dumps near the La Rosario vein, Capillitas epithermal deposit, Catamarca Province, Argentina (type locality)

Field-hunting tip

Where it forms: In an epithermal bornite-rich ore in a copper, silver, and gold deposit. If you start seeing bornite, digenite, chalcocite in float, you are in the right ground. Typical habit: aggregates, granular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify catamarcaite?+

Mohs hardness is 3.5. Luster: metallic. The streak is black. Common colors include gray.

Where is catamarcaite found?+

Notable localities include Old dumps near the La Rosario vein, Capillitas epithermal deposit, Catamarca Province, Argentina (type locality).

Is catamarcaite safe to handle?+

Catamarcaite contains copper. Contains copper and potentially harmful trace elements; handle with care and wash hands after touching, as with most sulfide minerals.

What rocks look like catamarcaite?+

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

What minerals are found with catamarcaite?+

Catamarcaite commonly co-occurs with Bornite, Digenite, Chalcocite, Covellite, Sphalerite, Hübnerite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does catamarcaite form in?+

Where it forms: In an epithermal bornite-rich ore in a copper, silver, and gold deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is catamarcaite used for?+

Catamarcaite is used in collector.

Find catamarcaite on the map

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