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, 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.