Pearceite is a silver arsenic sulfosalt often found as distinct, triangular or hexagonal tabular crystals in silver-rich hydrothermal deposits. It is frequently associated with other silver minerals and is highly sought after by systematic mineral collectors for its sharp crystal morphology and metallic luster.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineraluncommonPearceite-Polybasite Group family

Pearceite

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

Is this pearceite?

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 pearceite with a known reference. Pearceite 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. Pearceite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Pearceite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: black, dark gray.
5
Look at form & habit
Crystal system: trigonal. Typical habit: tabular hexagonal crystals, triangular prisms, massive.

Often confused with

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

Often found alongside pearceite

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

All properties

Chemical formula: [Ag₆As₂S₇][Ag₉CuS₄]
Mohs hardness: 3
Density: 6.1-6.3 g/cm³
Colors: Black Dark Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Trigonal
Crystal habit: Tabular Hexagonal Crystals, Triangular Prisms, Massive
Cleavage: None
Rarity: Uncommon
Uses: Collector, Ore Mineral
Host rock: Hydrothermal Silver-rich Veins
Typical price: $20-150 thumbnail, $200+ cabinet specimen

Where rockhounds find pearceite

Classic worldwide localities

Montana, USA
Chihuahua, Mexico
Freiberg, Germany
Jachymov, Czech Republic

Field-hunting tip

Look in hydrothermal silver-rich veins country — that is the host setting where pearceite typically forms. If you start seeing proustite, pyrargyrite, stephanite in float, you are in the right ground. Field specimens usually show a tabular hexagonal crystals, triangular prisms, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify pearceite?+

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

Where is pearceite found?+

Notable localities include Montana, USA; Chihuahua, Mexico; Freiberg, Germany; Jachymov, Czech Republic.

How much is pearceite worth?+

Typical asking prices fall in the range of $20-150 thumbnail, $200+ cabinet specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is pearceite safe to handle?+

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

What rocks look like pearceite?+

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

What minerals are found with pearceite?+

Pearceite commonly co-occurs with Proustite, Pyrargyrite, Stephanite, Silver, Galena. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does pearceite form in?+

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

What is pearceite used for?+

Pearceite is used in collector, ore mineral.

Find pearceite on the map

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