Calciotantite is an exceptionally rare calcium tantalum oxide mineral that typically occurs as small, tabular crystals within highly fractionated granitic pegmatites. Collectors primarily find this species as micro-crystals associated with other rare tantalum-bearing minerals in complex lithium-cesium-tantalum (LCT) pegmatite systems.
Is this calciotantite?
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 calciotantite with a known reference. Calciotantite sits at Mohs 6.5, 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.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: hexagonal, inclusions, square.
Often found alongside calciotantite
Minerals reported to co-occur with calciotantite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaTa₄O₁₁
- Mohs hardness
- 6.5
- Density
- 7.46 g/cm³
- Colors
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Hexagonal, inclusions, square
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the albite-spodumene zone of granite pegmatites
Where rockhounds find calciotantite
Classic worldwide localities
- Mt. Vasin-Myl’k, Voron’i massif, Kola Peninsula, Russia
- Ungursai, eastern Kazakhstan
- Manono pegmatite, Katanga Province, Congo (Shaba Province, Zaire)
- Northern Nyköpingsgruvan granitic pegmatite, island of Utö, Stockholm Archipelago, Sweden
Field-hunting tip
Where it forms: In the albite-spodumene zone of granite pegmatites. If you start seeing microlite, scheelite, wodginite in float, you are in the right ground. Typical habit: hexagonal, inclusions, square. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify calciotantite?+
Where is calciotantite found?+
What minerals are found with calciotantite?+
What kind of rock does calciotantite form in?+
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Find calciotantite on the map
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