Alumotantite is an extremely rare aluminum-tantalum oxide mineral found in highly evolved granite pegmatites. It typically appears as small, colorless to pale yellow, transparent tabular crystals that can be difficult to distinguish from other rare tantalate species without chemical analysis.
Is this alumotantite?
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 alumotantite with a known reference. Alumotantite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Alumotantite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Alumotantite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals.
Often confused with
Alumotantite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside alumotantite
Minerals reported to co-occur with alumotantite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AlTaO₄
- Mohs hardness
- 6
- Density
- 5.68 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $200-1000+ per specimen depending on size
Where rockhounds find alumotantite
Classic worldwide localities
- Koktokay pegmatite, Altay Mountains, China
- Mawi pegmatite, Nuristan, Afghanistan
Field-hunting tip
Look in granite pegmatites country — that is the host setting where alumotantite typically forms. If you start seeing microcline, albite, quartz in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify alumotantite?+
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How much is alumotantite worth?+
What rocks look like alumotantite?+
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Find alumotantite on the map
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