Fluornatropyrochlore is a rare member of the pyrochlore group characterized by its sodium and fluorine dominance in the crystal structure. It typically forms sharp, lustrous octahedral crystals in alkaline igneous environments. Collectors should be aware of its inherent radioactivity due to common thorium and uranium substitution.
Is this fluornatropyrochlore?
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 fluornatropyrochlore with a known reference. Fluornatropyrochlore sits at Mohs 4-4.5, 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.
- 4Match the color rangeCompare against the expected color range: brownish yellow, reddish orange.
- 5Look at form & habitCrystal system: cubic. Typical habit: octahedral crystals.
Often confused with
Fluornatropyrochlore vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Fluornatropyrochlore leaves light yellow, Pyrochlore leaves brown; luster reads adamantine on Fluornatropyrochlore and vitreous to resinous on Pyrochlore.
How to tell apart: Zircon is the harder of the two (Mohs 7.5 vs. 4-4.5); streak differs, so Fluornatropyrochlore leaves light yellow, Zircon leaves white; luster reads adamantine on Fluornatropyrochlore and vitreous to adamantine; greasy when metamict on Zircon.
Often found alongside fluornatropyrochlore
Minerals reported to co-occur with fluornatropyrochlore. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,Pb,Ca,REE,U)₂Nb₂O₆F
- Mohs hardness
- 4-4.5
- Density
- 5.275 g/cm³
- Streak
- Light yellow
- Luster
- Adamantine
- Transparency
- Translucent to transparent
- Crystal system
- Cubic
- Crystal habit
- Octahedral crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An accessory phase in niobium-tantalum-rich alkali syenite
Where rockhounds find fluornatropyrochlore
Classic worldwide localities
- Boziguoer REE deposit, 43 km north of Baicheng County City, Baicheng County, Akesu, Xinjiang Autonomous Region, China
Field-hunting tip
Where it forms: An accessory phase in niobium-tantalum-rich alkali syenite. If you start seeing microcline, albite, aegirine in float, you are in the right ground. Typical habit: octahedral crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify fluornatropyrochlore?+
Where is fluornatropyrochlore found?+
Is fluornatropyrochlore safe to handle?+
What rocks look like fluornatropyrochlore?+
What minerals are found with fluornatropyrochlore?+
What kind of rock does fluornatropyrochlore form in?+
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Find fluornatropyrochlore on the map
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