Sinnerite is an extremely rare copper arsenic sulfide primarily known from the famous Lengenbach locality in the Binntal, Switzerland. It usually appears as small, metallic grey to black grains embedded within dolomitic marble and is primarily of interest to systematic mineral collectors.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrare

Sinnerite

Hardness: 3.5
Luster: Metallic
Streak: Black
Transparency: Opaque

Is this sinnerite?

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 sinnerite with a known reference. Sinnerite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Sinnerite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Sinnerite 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: trigonal. Typical habit: massive, anhedral grains.

Often confused with

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

mineral

Enargite

Mohs 3

How to tell apart: Streak differs — Sinnerite leaves black, Enargite leaves grayish-black.

Compare →

Often found alongside sinnerite

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

All properties

Chemical formula: Cu₆As₄S₉
Mohs hardness: 3.5
Density: 5.34 g/cm³
Colors: Gray Black
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Trigonal
Crystal habit: Massive, Anhedral Grains
Cleavage: None Observed
Rarity: Rare
Uses: Collector
Host rock: Dolomitic Marble
Typical price: $50-500 thumbnail

Where rockhounds find sinnerite

Classic worldwide localities

Lengenbach Quarry, Switzerland

Field-hunting tip

Look in dolomitic marble country — that is the host setting where sinnerite typically forms. If you start seeing realgar, orpiment, pyrite in float, you are in the right ground. Field specimens usually show a massive, anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify sinnerite?+

Mohs hardness is 3.5. It typically shows a metallic luster. The streak is black. Common colors include gray, black.

Where is sinnerite found?+

Notable localities include Lengenbach Quarry, Switzerland.

How much is sinnerite worth?+

Typical asking prices fall in the range of $50-500 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.

Is sinnerite safe to handle?+

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

What rocks look like sinnerite?+

Sinnerite is most often confused with Enargite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with sinnerite?+

Sinnerite commonly co-occurs with Realgar, Orpiment, Pyrite, Sartorite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does sinnerite form in?+

Sinnerite typically forms in dolomitic marble. Working float back to the host body is the standard way to chase a fresh occurrence.

What is sinnerite used for?+

Sinnerite is used in collector.

Find sinnerite on the map

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