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 4, 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: adamantine to dull.
- 4Match the color rangeCompare against the expected color range: green, yellowish, gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: aggregates, spherical.
Often confused with
Sphaerobismoite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Sphaerobismoite leaves white, Bismite leaves gray to yellow; luster reads adamantine to dull on Sphaerobismoite and subadamantine to dull, 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, waxy, may be dull to earthy 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
- 4
- Density
- 7.17 g/cm³
- Streak
- White
- Luster
- Adamantine to dull
- Transparency
- Semitransparent
- Crystal system
- Tetragonal
- Crystal habit
- Aggregates, spherical
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An oxidation product of wittichenite and emplectite
Where rockhounds find sphaerobismoite
Classic worldwide localities
- Neubulach, and at Schmiedestollen-Holde, near Wittichen, Black Forest, Germany
Field-hunting tip
Where it forms: An oxidation product of wittichenite and emplectite. If you start seeing bismutite, mixite, malachite in float, you are in the right ground. Typical habit: aggregates, spherical. 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?+
What is sphaerobismoite used for?+
Find sphaerobismoite on the map
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