Niocalite is a rare calcium niobium silicate mineral primarily found in carbonatite complexes. Collectors should look for its distinctive yellow-to-amber prismatic crystals and its characteristically strong bright yellow fluorescence under shortwave ultraviolet light.
Is this niocalite?
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 niocalite with a known reference. Niocalite 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. Niocalite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Niocalite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-orange, amber, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, acicular, radiating aggregates.
Often confused with
Niocalite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside niocalite
Minerals reported to co-occur with niocalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₁₄Nb₄Si₈O₃₇F₄
- Mohs hardness
- 6
- Density
- 3.31 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, Acicular, Radiating Aggregates
- Cleavage
- Poor
- Fluorescence
- Bright Yellow Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Carbonatites
- Typical price
- $20-150 thumbnail, $200+ cabinet
Where rockhounds find niocalite
Classic worldwide localities
- Oka Complex, Quebec, Canada
Field-hunting tip
Look in carbonatites country — that is the host setting where niocalite typically forms. If you start seeing calcite, apatite, diopside in float, you are in the right ground. Field specimens usually show a prismatic, acicular, radiating aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find niocalite on the map
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