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.

Hardness

2-3

Mohs

Luster

Metallic

Streak

Black

Transparency

Opaque

mineralrareEucairite Group family

Brontesite

Hardness: 2-3
Luster: Metallic
Streak: Black
Transparency: Opaque

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Is this brontesite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch brontesite with a known reference. Brontesite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Brontesite leaves a black streak.
3
Read the luster
Hold the specimen under a strong light. Brontesite typically shows a metallic luster.
4
Match the color range
Compare against the expected color range: gray, white.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: granular aggregates.

Often confused with

Brontesite vs. its common look-alikes, and how to tell them apart in the field.

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: Pb₃CuTe₃Cl₂
Mohs hardness: 2-3
Density: 7.3 g/cm³
Colors: Gray White
Streak: Black
Luster: Metallic
Transparency: Opaque
Crystal system: Hexagonal
Crystal habit: Granular Aggregates
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $100-500 per specimen

Where rockhounds find brontesite

Classic worldwide localities

Otto Mountain, California, USA

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?+

Mohs hardness is 2-3. It typically shows a metallic luster. The streak is black. Common colors include gray, white.

Where is brontesite found?+

Notable localities include Otto Mountain, California, USA.

How much is brontesite worth?+

Typical asking prices fall in the range of $100-500 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is brontesite safe to handle?+

It contains toxic constituents. Contains lead and tellurium; handle with care and wash hands thoroughly after handling. Do not ingest or inhale dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like brontesite?+

Brontesite is most often confused with Eucairite, Klaprothite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with brontesite?+

Brontesite commonly co-occurs with Quartz, Hematite, Gold, Lead-tellurides. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does brontesite form in?+

Brontesite typically forms in hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is brontesite used for?+

Brontesite is used in collector.

Find brontesite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.