Boleite is a striking, deep indigo-blue mineral famous for forming perfect cubic crystals. It is primarily found in oxidized marine-type copper deposits where it forms as a rare secondary mineral alongside other silver and lead halides.
Is this boleite?
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 boleite with a known reference. Boleite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: blue, with greenish tint.
- 3Read the lusterHold the specimen under a strong light. Luster: weakly vitreous; pearly on cleavage surfaces.
- 4Match the color rangeCompare against the expected color range: indigo blue, dark blue, light blue.
- 5Look at form & habitCrystal system: cubic. Typical habit: pseudo cubic.
Often confused with
Boleite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Boleite leaves blue, with greenish tint, Pseudoboleite leaves light green; luster reads weakly vitreous; pearly on cleavage surfaces on Boleite and pearly on cleavages on Pseudoboleite.
How to tell apart: Streak differs, so Boleite leaves blue, with greenish tint, Cumengeite leaves sky-blue.
Often found alongside boleite
Minerals reported to co-occur with boleite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KPb₂₆Ag₉Cu₂₄Cl₆₂(OH)₄₈
- Mohs hardness
- 3-3.5
- Density
- 5.054 g/cm³
- Colors
- Streak
- Blue, with greenish tint
- Luster
- Weakly vitreous; pearly on cleavage surfaces
- Transparency
- Translucent to opaque
- Crystal system
- Cubic
- Crystal habit
- Pseudo cubic
- Cleavage
- {001}, perfect
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- A secondary mineral formed through reaction of chloride with primary sulfides in the oxidized zone of Pb–Cu deposits; in smelter slag immersed in and leached by sea water
Where rockhounds find boleite
Classic worldwide localities
- Mammoth-St. Anthony mine, Tiger, and the Vekol mine, Pinal Co., USA
- Apache mine, Gila Co., USA
- Rowley mine, Maricopa Co., Arizona, USA
- Philipsburg, Granite Co., Montana, USA
- Amelia mine, Boleo, near Santa Rosalía, Baja California, Mexico
- Laurium, Greece, in slag
Field-hunting tip
Where it forms: A secondary mineral formed through reaction of chloride with primary sulfides in the oxidized zone of Pb–Cu deposits; in smelter slag immersed in and leached by sea water. If you start seeing pseudoboleite, cumengeite, atacamite in float, you are in the right ground. Typical habit: pseudo cubic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify boleite?+
Where is boleite found?+
Is boleite safe to handle?+
What rocks look like boleite?+
What minerals are found with boleite?+
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Find boleite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
