Cupropearceite is a rare copper-dominant member of the pearceite group, appearing as dark, metallic hexagonal plates or massive aggregates. It is typically found in low-to-medium temperature hydrothermal sulfide deposits and requires chemical analysis or X-ray diffraction to reliably distinguish from other members of the tennantite-pearceite series.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrarePearceite-Tennantite Series family

Cupropearceite

Hardness: 3
Luster: Metallic
Streak: Black
Transparency: Opaque

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Is this cupropearceite?

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 cupropearceite with a known reference. Cupropearceite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Cupropearceite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Cupropearceite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black, iron-black.
5
Look at form & habit
Crystal system: trigonal. Typical habit: tabular crystals, hexagonal plates, massive.

Often confused with

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

Often found alongside cupropearceite

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

All properties

Chemical formula: (Cu,Ag)₁₆As₂S₁₁
Mohs hardness: 3
Density: 6.2 g/cm³
Colors: Black Iron-black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Trigonal
Crystal habit: Tabular Crystals, Hexagonal Plates, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins in Sedimentary and Metamorphic Rocks
Typical price: $50-300 per specimen

Where rockhounds find cupropearceite

Classic worldwide localities

Dzhezkazgan, Kazakhstan
Rudabanya, Hungary
Guanajuato, Mexico

Field-hunting tip

Look in hydrothermal veins in sedimentary and metamorphic rocks country, the host setting where cupropearceite typically forms. If you start seeing tennantite, galena, sphalerite in float, you are in the right ground. Field specimens usually show a tabular crystals, hexagonal plates, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify cupropearceite?+

Mohs hardness is 3. It typically shows a metallic luster. The streak is black. Common colors include black, iron-black.

Where is cupropearceite found?+

Notable localities include Dzhezkazgan, Kazakhstan; Rudabanya, Hungary; Guanajuato, Mexico.

How much is cupropearceite worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is cupropearceite safe to handle?+

It contains toxic constituents. Contains arsenic and copper; avoid dust inhalation and wash hands thoroughly after handling specimens. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like cupropearceite?+

Cupropearceite is most often confused with Pearceite, Polybasite, Tetrahedrite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with cupropearceite?+

Cupropearceite commonly co-occurs with Tennantite, Galena, Sphalerite, Calcite, Dolomite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does cupropearceite form in?+

Cupropearceite typically forms in hydrothermal veins in sedimentary and metamorphic rocks. Working float back to the host body is the standard way to chase a fresh occurrence.

What is cupropearceite used for?+

Cupropearceite is used in collector.

Find cupropearceite on the map

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