Giraudite-(Zn) is a rare member of the tetrahedrite group characterized by its high selenium content. It typically forms metallic, dark-grey tetrahedral crystals often found in hydrothermal selenium-bearing deposits.

Hardness

3-4

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareTetrahedrite Group family

Giraudite-(Zn)

Hardness: 3-4
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this giraudite-(zn)?

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 giraudite-(zn) with a known reference. Giraudite-(Zn) sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Giraudite-(Zn) leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Giraudite-(Zn) typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: gray, black.
5
Look at form & habit
Crystal system: cubic. Typical habit: tetrahedral crystals, massive.

Often confused with

Giraudite-(Zn) vs. its common look-alikes — and how to tell them apart in the field.

Often found alongside giraudite-(zn)

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

All properties

Chemical formula: (Cu,Zn,Ag)₁₂As₄(Se,S)₁₃
Mohs hardness: 3-4
Density: 5.1-5.3 g/cm³
Colors: Gray Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Tetrahedral Crystals, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-300 per specimen

Where rockhounds find giraudite-(zn)

Classic worldwide localities

Trogtal quarry, Germany
Guerguet, Morocco
San Jose mine, Bolivia

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where giraudite-(zn) typically forms. If you start seeing clausthalite, berzelianite, hematite in float, you are in the right ground. Field specimens usually show a tetrahedral crystals, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify giraudite-(zn)?+

Mohs hardness is 3-4. It typically shows a metallic luster. The streak is black. Common colors include gray, black.

Where is giraudite-(zn) found?+

Notable localities include Trogtal quarry, Germany; Guerguet, Morocco; San Jose mine, Bolivia.

How much is giraudite-(zn) 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 giraudite-(zn) safe to handle?+

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

What rocks look like giraudite-(zn)?+

Giraudite-(Zn) is most often confused with Tetrahedrite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with giraudite-(zn)?+

Giraudite-(Zn) commonly co-occurs with Clausthalite, Berzelianite, Hematite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does giraudite-(zn) form in?+

Giraudite-(Zn) typically forms in hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is giraudite-(zn) used for?+

Giraudite-(Zn) is used in collector.

Find giraudite-(zn) on the map

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