Larosite is a rare sulfosalt mineral primarily identified through microanalysis in hydrothermal ore deposits. It typically occurs as tiny, metallic grains embedded within other sulfide minerals, making it a challenging but rewarding find for systematic mineral collectors.

Hardness

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Larosite

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

Is this larosite?

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 larosite with a known reference. Larosite 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. Larosite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Larosite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: white, pale gray.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: grains.

Often confused with

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

Often found alongside larosite

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

All properties

Chemical formula: (Cu,Ag)₂₁Pb₂As₇S₁₃
Mohs hardness: 3
Density: 7.59 g/cm³
Colors: White Pale Gray
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Grains
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-300 per small specimen

Where rockhounds find larosite

Classic worldwide localities

Jas Roux deposit, Hautes-Alpes, France

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where larosite typically forms. If you start seeing tennantite, chalcopyrite, galena in float, you are in the right ground. Field specimens usually show a grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify larosite?+

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

Where is larosite found?+

Notable localities include Jas Roux deposit, Hautes-Alpes, France.

How much is larosite worth?+

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

Is larosite safe to handle?+

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

What rocks look like larosite?+

Larosite 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 larosite?+

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

What kind of rock does larosite form in?+

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

What is larosite used for?+

Larosite is used in collector.

Find larosite on the map

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