Gebhardite is a rare lead arsenic oxychloride mineral typically found as small, fragile, yellow to yellowish-brown platy crystals. It is best known from the Tsumeb mine in Namibia, where it occurs as a secondary mineral in the oxidized zones of ore deposits. Due to its high lead and arsenic content, specimens should be handled with caution and stored away from reach.

Hardness

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Gebhardite

Hardness: ~3
Luster: Adamantine
Streak: White
Transparency: Transparent

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Is this gebhardite?

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 gebhardite with a known reference. Gebhardite 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. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: adamantine.
4
Match the color range
Compare against the expected color range: light brown.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy or tabular crystals.

Often confused with

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

How to tell apart: Luster reads adamantine on Gebhardite and resinous to subadamantine on Mimetite.

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Often found alongside gebhardite

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

All properties

Chemical formula: Pb₈(As₂O₅)₂OCl₆
Mohs hardness: ~3
Density: 6 g/cm³
Colors: Light brown
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Platy or tabular crystals
Cleavage: {001}, perfect; {010}, good
Rarity: Rare
Uses: Collector
Host rock: On a specimen of highly oxidized ore from the lower oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit

Where rockhounds find gebhardite

Classic worldwide localities

Tsumeb, Namibia

Field-hunting tip

Where it forms: On a specimen of highly oxidized ore from the lower oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit. If you start seeing reinerite, mimetite, smithsonite in float, you are in the right ground. Typical habit: platy or tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gebhardite?+

Mohs hardness is ~3. Luster: adamantine. The streak is white. Common colors include light brown.

Where is gebhardite found?+

Notable localities include Tsumeb, Namibia.

Is gebhardite safe to handle?+

Gebhardite contains arsenic and lead and calls for real care. Contains both lead and arsenic; handle with care, wash hands after handling, and avoid creating dust.

What rocks look like gebhardite?+

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

What minerals are found with gebhardite?+

Gebhardite commonly co-occurs with Reinerite, Mimetite, Smithsonite, Willemite, Hematite, Fraipontite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gebhardite form in?+

Where it forms: On a specimen of highly oxidized ore from the lower oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gebhardite used for?+

Gebhardite is used in collector.

Find gebhardite on the map

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