Capgaronnite is an extremely rare mercury-silver halide mineral named after its type locality at the Cap Garonne mine in France. It typically forms small, clear, tabular crystals in supergene environments where lead and copper-rich ores have undergone alteration.
Is this capgaronnite?
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 capgaronnite with a known reference. Capgaronnite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Capgaronnite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Capgaronnite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals.
Often confused with
Capgaronnite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads adamantine on Capgaronnite and vitreous on Halite.
How to tell apart: Luster reads adamantine on Capgaronnite and resinous on Chlorargyrite.
How to tell apart: Streak differs, so Capgaronnite leaves white, Boleite leaves light blue; luster reads adamantine on Capgaronnite and vitreous on Boleite.
Often found alongside capgaronnite
Minerals reported to co-occur with capgaronnite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- HgAgClBrI
- Mohs hardness
- 2.5
- Density
- 7.39 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular Crystals
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sedimentary Copper Deposits
- Typical price
- $100-500+ depending on crystal size and quality
Where rockhounds find capgaronnite
Classic worldwide localities
- Cap Garonne mine, Var, France
Field-hunting tip
Look in sedimentary copper deposits country, the host setting where capgaronnite typically forms. If you start seeing quartz, galena, barite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify capgaronnite?+
Where is capgaronnite found?+
How much is capgaronnite worth?+
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Find capgaronnite on the map
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