Mummeite is a rare sulfosalt mineral primarily found as part of the lillianite homologous series. It typically presents as metallic lead-gray massive grains within hydrothermal ore deposits associated with other sulfide minerals.

Hardness

3.5

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareLillianite Homologous Series family

Mummeite

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

Is this mummeite?

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 mummeite with a known reference. Mummeite 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. Mummeite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Mummeite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: lead-gray, grayish-white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: massive to fine-grained aggregates, rarely acicular crystals.

Often confused with

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

mineral

Lillianite

Mohs 2.5

How to tell apart: Mummeite is noticeably harder (Mohs 3.5 vs. 2.5).

How to tell apart: Mummeite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs, so Mummeite leaves black, Galena leaves lead-gray.

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Often found alongside mummeite

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

All properties

Chemical formula: Ag₃.25CuPb₂.5Bi₆.75S₁₆
Mohs hardness: 3.5
Density: 6.87 g/cm³
Colors: Lead-gray Grayish-white
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Monoclinic
Crystal habit: Massive to Fine-grained Aggregates, Rarely Acicular Crystals
Cleavage: None Observed
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-300 per specimen

Where rockhounds find mummeite

Classic worldwide localities

Junin Province, Peru
Torrington, New South Wales, Australia

Field-hunting tip

Look in hydrothermal veins country, the host setting where mummeite typically forms. If you start seeing galena, pyrite, quartz in float, you are in the right ground. Field specimens usually show a massive to fine-grained aggregates, rarely acicular crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify mummeite?+

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

Where is mummeite found?+

Notable localities include Junin Province, Peru; Torrington, New South Wales, Australia.

How much is mummeite 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 mummeite safe to handle?+

It contains toxic constituents. Contains lead and bismuth; handle with care and wash hands thoroughly after handling. Do not inhale dust or ingest. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like mummeite?+

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

What minerals are found with mummeite?+

Mummeite commonly co-occurs with Galena, Pyrite, Quartz, Bismuthinite, Tetrahedrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does mummeite form in?+

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

What is mummeite used for?+

Mummeite is used in collector.

Find mummeite on the map

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