Bismutotantalite is a very rare bismuth tantalate mineral found primarily in complex granitic pegmatites. It is sought after by mineral collectors for its high density and characteristic prismatic crystal habits, which are often found associated with other rare earth minerals.
Is this bismutotantalite?
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 bismutotantalite with a known reference. Bismutotantalite sits at Mohs 5.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bismutotantalite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Bismutotantalite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellowish-brown, brown, black, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic to tabular crystals, often embedded.
Often confused with
Bismutotantalite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Bismutotantalite leaves white, Tantalite leaves black to reddish-brown; luster reads vitreous on Bismutotantalite and submetallic to resinous on Tantalite.
How to tell apart: Luster reads vitreous on Bismutotantalite and adamantine on Stibiotantalite.
Often found alongside bismutotantalite
Minerals reported to co-occur with bismutotantalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BiTaO₄
- Mohs hardness
- 5.5
- Density
- 8.1-8.2 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic to Tabular Crystals, Often Embedded
- Cleavage
- Distinct in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-500 thumbnail specimen
Where rockhounds find bismutotantalite
Classic worldwide localities
- Uganda
- Democratic Republic of the Congo
- Brazil
- Mozambique
Field-hunting tip
Look in granite pegmatites country — that is the host setting where bismutotantalite typically forms. If you start seeing beryl, muscovite, columbite in float, you are in the right ground. Field specimens usually show a prismatic to tabular crystals, often embedded habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bismutotantalite?+
Where is bismutotantalite found?+
How much is bismutotantalite worth?+
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What rocks look like bismutotantalite?+
What minerals are found with bismutotantalite?+
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Find bismutotantalite on the map
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