Gallite is a very rare copper-gallium sulfide that typically occurs as microscopic inclusions or fine-grained masses within other sulfide ores. Collectors generally find it in material originating from the Tsumeb mine in Namibia, where it is often associated with other rare germanium-bearing minerals.
Is this gallite?
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 gallite with a known reference. Gallite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray-black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: massive, anhedral grains.
Often confused with
Gallite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Gallite leaves gray-black, Chalcopyrite leaves greenish black.
How to tell apart: Streak differs, so Gallite leaves gray-black, Sphalerite leaves pale brown to pale yellow and white; luster reads metallic on Gallite and resinous to adamantine on Sphalerite.
How to tell apart: Streak differs, so Gallite leaves gray-black, Stannite leaves blackish.
Often found alongside gallite
Minerals reported to co-occur with gallite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CuGaS₂
- Mohs hardness
- 3-3.5
- Density
- 4.2 g/cm³
- Colors
- Streak
- Gray-black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Massive, anhedral grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In base-metal vein deposits with relatively high gallium content
Where rockhounds find gallite
Classic worldwide localities
- Tsumeb, Namibia (type locality)
- Congo (Zaire), at Kipushi, 28 km southwest of Lubumbashi, Katanga (Shaba) Province
- Radka deposit, Pazardzhik, and the Chelopech deposit, Sofia, Bulgaria
- Northwestern Pinar del Rio Province, Cuba
- Yauricocha, Peru
Field-hunting tip
Where it forms: In base-metal vein deposits with relatively high gallium content. If you start seeing reniérite, germanite, bornite in float, you are in the right ground. Typical habit: massive, anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
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Find gallite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
