Oxynatromicrolite is a rare member of the pyrochlore supergroup occurring primarily in tantalum-rich granitic pegmatites. It is typically found as small, octahedral crystals or massive grains and is highly sought after by collectors specializing in complex oxide species.
Is this oxynatromicrolite?
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 oxynatromicrolite with a known reference. Oxynatromicrolite 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: yellowish brown.
- 3Read the lusterHold the specimen under a strong light. Luster: greasy to waxy.
- 4Match the color rangeCompare against the expected color range: brown, yellowish brown.
- 5Look at form & habitCrystal system: cubic. Typical habit: octahedral crystals, massive.
Often confused with
Oxynatromicrolite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside oxynatromicrolite
Minerals reported to co-occur with oxynatromicrolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,Ca,U)₂(Ta,Nb)₂O₆(O,F)
- Mohs hardness
- ~5
- Density
- 6.580 g/cm³
- Colors
- Streak
- Yellowish brown
- Luster
- Greasy to waxy
- Transparency
- Translucent
- Crystal system
- Cubic
- Crystal habit
- Octahedral crystals, massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a rare-element granitic pegmatite, crystallized from a highly evolved felsic magma or transitional magmatic-hydrothermal fluids enriched in volatile, flux and lithophile elements
Where rockhounds find oxynatromicrolite
Classic worldwide localities
- Sweden
- Russia
- Brazil
- Canada
Field-hunting tip
Where it forms: In a rare-element granitic pegmatite, crystallized from a highly evolved felsic magma or transitional magmatic-hydrothermal fluids enriched in volatile, flux and lithophile elements. If you start seeing quartz, albite, potassium feldspar in float, you are in the right ground. Typical habit: octahedral crystals, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify oxynatromicrolite?+
Where is oxynatromicrolite found?+
Is oxynatromicrolite safe to handle?+
What rocks look like oxynatromicrolite?+
What minerals are found with oxynatromicrolite?+
What kind of rock does oxynatromicrolite form in?+
What is oxynatromicrolite used for?+
Find oxynatromicrolite on the map
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