Gananite is a rare bismuth halide that forms brown to black irregular aggregates. It occurs in wolframite-bearing quartz veins. Associated minerals include bismuth, bismuthinite and pyrite. It was first described from Ganan area, Laikeng district, southern Jiangxi Province, China.
Is this gananite?
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 gananite with a known reference. Gananite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: dark gray.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous to semimetallic.
- 4Match the color rangeCompare against the expected color range: brown, black, greenish black.
- 5Look at form & habitCrystal system: cubic. Typical habit: aggregates, irregular grains.
Often confused with
Gananite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Sillimanite is the harder of the two (Mohs 6.5-7.5 vs. 3.5); streak differs, so Gananite leaves dark gray, Sillimanite leaves white; luster reads resinous to semimetallic on Gananite and vitreous to subadamantine on Sillimanite.
How to tell apart: Bismite is the harder of the two (Mohs 4.5 vs. 3.5); streak differs, so Gananite leaves dark gray, Bismite leaves gray to yellow; luster reads resinous to semimetallic on Gananite and subadamantine to dull, earthy on Bismite.
Often found alongside gananite
Minerals reported to co-occur with gananite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BiF₃
- Mohs hardness
- 3.5
- Density
- 8.928 g/cm³
- Colors
- Streak
- Dark gray
- Luster
- Resinous to semimetallic
- Transparency
- Translucent
- Crystal system
- Cubic
- Crystal habit
- Aggregates, irregular grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In wolframite-bearing quartz veins
Where rockhounds find gananite
Classic worldwide localities
- Ganan area, Laikeng district, southern Jiangxi Province, China
Field-hunting tip
Where it forms: In wolframite-bearing quartz veins. If you start seeing bismuth, bismuthinite, pyrite in float, you are in the right ground. Typical habit: aggregates, irregular grains. Train your eye for that shape before scanning the outcrop.
Common questions
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Find gananite on the map
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