Mückeite is an exceptionally rare sulfosalt mineral primarily identified from hydrothermal vein deposits. It typically occurs as minute, yellowish metallic grains intimately associated with other bismuth and nickel-bearing sulfides.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Grayish black

Transparency

Opaque

mineralrare

Mückeite

Hardness: 3.5
Luster: Metallic
Streak: Grayish black
Transparency: Opaque

Is this mückeite?

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 mückeite with a known reference. Mückeite 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. Streak: grayish black.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: pale gray.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular.

Often confused with

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

mineral

Chalcopyrite

Mohs 3.5-4

How to tell apart: Streak differs, so Mückeite leaves grayish black, Chalcopyrite leaves greenish black.

How to tell apart: Ullmannite is the harder of the two (Mohs 5-5.5 vs. 3.5).

Compare →

Often found alongside mückeite

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

All properties

Chemical formula: CuNiBiS₃
Mohs hardness: 3.5
Density: 5.88 g/cm³
Colors: Pale gray
Streak: Grayish black
Luster: Metallic
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Tabular
Cleavage: Very good on {010}, good on {001}
Rarity: Rare
Uses: Collector
Host rock: In dump material at a polymetallic hydrothermal deposit, topotactically relacing lapieite

Where rockhounds find mückeite

Classic worldwide localities

Grüne Au mine, Schutzbach, 15 km southwest of Siegen, North Rhine-Westphalia, Germany (type locality)

Field-hunting tip

Where it forms: In dump material at a polymetallic hydrothermal deposit, topotactically relacing lapieite. If you start seeing lapieite, millerite, bismuthinite in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mückeite?+

Mohs hardness is 3.5. Luster: metallic. The streak is grayish black. Common colors include pale gray.

Where is mückeite found?+

Notable localities include Grüne Au mine, Schutzbach, 15 km southwest of Siegen, North Rhine-Westphalia, Germany (type locality).

Is mückeite safe to handle?+

Mückeite contains copper and nickel. Contains copper, nickel, bismuth, and sulfur; handle with care and wash hands thoroughly after handling. Do not ingest dust or inhale particles.

What rocks look like mückeite?+

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

What minerals are found with mückeite?+

Mückeite commonly co-occurs with Lapieite, Millerite, Bismuthinite, Sphalerite, Aikinite, Polydymite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mückeite form in?+

Where it forms: In dump material at a polymetallic hydrothermal deposit, topotactically relacing lapieite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is mückeite used for?+

Mückeite is used in collector.

Find mückeite on the map

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