Brontesite is a very rare lead copper telluride halide mineral discovered in the oxidized zones of lead-rich hydrothermal veins. It typically presents as microscopic granular aggregates associated with various tellurium-bearing minerals. Collectors prize it primarily for its extreme rarity and complex chemical composition.
Is this brontesite?
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 brontesite with a known reference. Brontesite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Brontesite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Brontesite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: gray, white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: granular aggregates.
Often confused with
Brontesite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Brontesite leaves white, Eucairite leaves black; luster reads vitreous on Brontesite and metallic on Eucairite.
How to tell apart: Streak differs, so Brontesite leaves white, Klaprothite leaves pale yellow-green.
Often found alongside brontesite
Minerals reported to co-occur with brontesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (NH₄)₃PbCl₅
- Mohs hardness
- 2-3
- Density
- 2.72 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Granular Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
Where rockhounds find brontesite
Classic worldwide localities
- La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy
Field-hunting tip
Look in hydrothermal veins country, the host setting where brontesite typically forms. If you start seeing quartz, hematite, gold in float, you are in the right ground. Field specimens usually show a granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify brontesite?+
Where is brontesite found?+
Is brontesite safe to handle?+
What rocks look like brontesite?+
What minerals are found with brontesite?+
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Find brontesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
