Sphaerobismoite is a rare bismuth oxide mineral typically found in the oxidation zones of bismuth-bearing hydrothermal veins. It often forms thin, platy crystals or radial clusters and is most commonly identified by its high density and pearly luster in the presence of other bismuth species.
Is this sphaerobismoite?
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 sphaerobismoite with a known reference. Sphaerobismoite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Sphaerobismoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Sphaerobismoite typically shows a adamantine to dull luster.
- 4Match the color rangeCompare against the expected color range: white, yellowish-white, gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: platy crystals, crusts, radial aggregates.
Often confused with
Sphaerobismoite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Bismite is the harder of the two (Mohs 4.5 vs. 3.5); streak differs, so Sphaerobismoite leaves white, Bismite leaves gray to yellow; luster reads adamantine to dull on Sphaerobismoite and subadamantine to dull to earthy on Bismite.
How to tell apart: Streak differs, so Sphaerobismoite leaves white, Bismutite leaves gray; luster reads adamantine to dull on Sphaerobismoite and vitreous to waxy to dull on Bismutite.
Often found alongside sphaerobismoite
Minerals reported to co-occur with sphaerobismoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Bi₂O₃
- Mohs hardness
- 3.5
- Density
- 7.17 g/cm³
- Colors
- Streak
- White
- Luster
- Adamantine to Dull
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Platy Crystals, Crusts, Radial Aggregates
- Cleavage
- Perfect Basal
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Oxidized Bismuth Deposits
Where rockhounds find sphaerobismoite
Classic worldwide localities
- Schneeberg, Saxony, Germany
- Joachimsthal, Czech Republic
- Bolivia
- Japan
Field-hunting tip
Look in hydrothermal veins in oxidized bismuth deposits country, the host setting where sphaerobismoite typically forms. If you start seeing bismuth, bismite, bismutite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify sphaerobismoite?+
Where is sphaerobismoite found?+
Is sphaerobismoite safe to handle?+
What rocks look like sphaerobismoite?+
What minerals are found with sphaerobismoite?+
What kind of rock does sphaerobismoite form in?+
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Find sphaerobismoite on the map
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