Bambollaite is an extremely rare copper selenium oxysalt mineral that occurs as small, dark blue, platy crystals. It is primarily found in the oxidized zones of selenium-rich hydrothermal deposits, most notably at its type locality in Sonora, Mexico.
Is this bambollaite?
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 bambollaite with a known reference. Bambollaite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bambollaite leaves a blue streak.
- 3Read the lusterHold the specimen under a strong light. Bambollaite typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: dark blue, black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: platy crystals, granular aggregates.
Often confused with
Bambollaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Bambollaite leaves blue, Chalcomenite leaves pale blue; luster reads submetallic on Bambollaite and vitreous on Chalcomenite.
How to tell apart: Streak differs, so Bambollaite leaves blue, Ahlfeldite leaves pinkish-white; luster reads submetallic on Bambollaite and vitreous on Ahlfeldite.
Often found alongside bambollaite
Minerals reported to co-occur with bambollaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄SeO₃(OH)₆
- Mohs hardness
- 2
- Density
- 4.2 g/cm³
- Streak
- Blue
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Platy Crystals, Granular Aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Hydrothermal Selenium Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find bambollaite
Classic worldwide localities
- Bambolla Mine, Moctezuma, Sonora, Mexico
Field-hunting tip
Look in oxidized hydrothermal selenium deposits country, the host setting where bambollaite typically forms. If you start seeing chalcomenite, quetzalcoatlite, moctezumite in float, you are in the right ground. Field specimens usually show a platy crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find bambollaite on the map
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