Fluorcalciopyrochlore is a rare member of the pyrochlore group characterized by its dominant calcium and fluorine content. It typically forms octahedral crystals in carbonatites and alkaline igneous rocks, often exhibiting brownish hues and radioactive properties due to potential uranium impurities.
Is this fluorcalciopyrochlore?
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 fluorcalciopyrochlore with a known reference. Fluorcalciopyrochlore sits at Mohs 5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine to greasy.
- 4Match the color rangeCompare against the expected color range: brownish yellow, reddish orange.
- 5Look at form & habitCrystal system: cubic. Typical habit: octahedral crystals, massive, granular.
Often confused with
Fluorcalciopyrochlore vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Fluorcalciopyrochlore leaves light yellow, Pyrochlore leaves brown; luster reads adamantine to greasy on Fluorcalciopyrochlore and vitreous to resinous on Pyrochlore.
How to tell apart: Zircon is the harder of the two (Mohs 7.5 vs. 5); streak differs, so Fluorcalciopyrochlore leaves light yellow, Zircon leaves white; luster reads adamantine to greasy on Fluorcalciopyrochlore and vitreous to adamantine; greasy when metamict on Zircon.
Often found alongside fluorcalciopyrochlore
Minerals reported to co-occur with fluorcalciopyrochlore. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ca,Na)₂(Nb,Ti)₂O₆F
- Mohs hardness
- 5
- Density
- 4.34 g/cm³
- Streak
- Light yellow
- Luster
- Adamantine to greasy
- Transparency
- Transparent to translucent
- Crystal system
- Cubic
- Crystal habit
- Octahedral crystals, massive, granular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific study
- Host rock
- In the dolomitic carbonatite
Where rockhounds find fluorcalciopyrochlore
Classic worldwide localities
- Bayan Obo REE-niobium deposit, Inner Mongolia, People’s Republic of China
Field-hunting tip
Where it forms: In the dolomitic carbonatite. If you start seeing dolomite, calcite, aegirine in float, you are in the right ground. Typical habit: octahedral crystals, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify fluorcalciopyrochlore?+
Where is fluorcalciopyrochlore found?+
Is fluorcalciopyrochlore safe to handle?+
What rocks look like fluorcalciopyrochlore?+
What minerals are found with fluorcalciopyrochlore?+
What kind of rock does fluorcalciopyrochlore form in?+
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Find fluorcalciopyrochlore on the map
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