Söhngeite is a rare gallium hydroxide mineral found almost exclusively in the oxidized zones of the Tsumeb Mine in Namibia. It typically occurs as small, sharp octahedral crystals or crusts associated with other secondary minerals in oxidized ore bodies.

Hardness

4-4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Semitransparent

mineralrare

Söhngeite

Hardness: 4-4.5
Luster: Vitreous
Streak: White
Transparency: Semitransparent

Is this söhngeite?

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 söhngeite with a known reference. Söhngeite sits at Mohs 4-4.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: white, pale yellow, pale brown, pale greenish yellow.
5
Look at form & habit
Crystal system: orthorhombic.

Often confused with

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

How to tell apart: Söhngeite is noticeably harder (Mohs 4-4.5 vs. 3).

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Often found alongside söhngeite

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

All properties

Chemical formula: Ga(OH)₃
Mohs hardness: 4-4.5
Density: 3.84 g/cm³
Colors: White Pale yellow Pale brown Pale greenish yellow
Streak: White
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Orthorhombic
Cleavage: None
Rarity: Rare
Uses: Collector, Research
Host rock: An alteration product of gallite-bearing germanite in an oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit

Where rockhounds find söhngeite

Classic worldwide localities

Tsumeb, Namibia

Field-hunting tip

Where it forms: An alteration product of gallite-bearing germanite in an oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit. If you start seeing germanite, gallite in float, you are in the right ground.

Common questions

How do you identify söhngeite?+

Mohs hardness is 4-4.5. Luster: vitreous. The streak is white. Common colors include white, pale yellow, pale brown, pale greenish yellow.

Where is söhngeite found?+

Notable localities include Tsumeb, Namibia.

What rocks look like söhngeite?+

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

What minerals are found with söhngeite?+

Söhngeite commonly co-occurs with Germanite, Gallite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does söhngeite form in?+

Where it forms: An alteration product of gallite-bearing germanite in an 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 söhngeite used for?+

Söhngeite is used in collector, research.

Find söhngeite on the map

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