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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless, 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 shining; 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 observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A product of fumarolic activity
Where rockhounds find brontesite
Classic worldwide localities
- La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy
Field-hunting tip
Where it forms: A product of fumarolic activity. If you start seeing bismuthinite, godovikovite, demicheleite- in float, you are in the right ground. Typical habit: granular aggregates. 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?+
What kind of rock does brontesite form in?+
What is brontesite used for?+
Find brontesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
