Gallobeudantite is a very rare member of the alunite supergroup known for its distinct yellowish rhombohedral crystals. It is typically found in the oxidized zones of complex base metal deposits, specifically where gallium is present as an trace impurity. Collectors prize it as a rare mineralogical curiosity from classic lead-zinc mining localities.
Is this gallobeudantite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch gallobeudantite with a known reference. Gallobeudantite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white to pale yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: pale yellow, slightly greenish yellow, cream.
- 5Look at form & habitCrystal system: trigonal. Typical habit: disseminated, rhombohedral crystals.
Often confused with
Gallobeudantite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Gallobeudantite leaves white to pale yellow, Beudantite leaves grayish yellow to green.
How to tell apart: Streak differs, so Gallobeudantite leaves white to pale yellow, Segnitite leaves pale yellow.
Often found alongside gallobeudantite
Minerals reported to co-occur with gallobeudantite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbGa₃(AsO₄)(SO₄)(OH)₆
- Mohs hardness
- 4
- Density
- 4.58 g/cm³
- Colors
- Streak
- White to pale yellow
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Disseminated, rhombohedral crystals
- Cleavage
- Indistinct on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in vugs in oxidized ore from a dolostone-hosted hydrothermal polymetallic ore deposit
Where rockhounds find gallobeudantite
Classic worldwide localities
- Tsumeb, Namibia
Field-hunting tip
Where it forms: A rare secondary mineral in vugs in oxidized ore from a dolostone-hosted hydrothermal polymetallic ore deposit. If you start seeing stolzite, mercurian silver, otjisumeite in float, you are in the right ground. Typical habit: disseminated, rhombohedral crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify gallobeudantite?+
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What rocks look like gallobeudantite?+
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Find gallobeudantite on the map
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