Villiaumite is a rare sodium fluoride mineral prized by collectors for its vibrant carmine-red color, though it is highly sensitive to light and may fade or become dull if exposed for extended periods. It is primarily found in alkaline igneous rocks like nepheline syenites and is best preserved in a cool, dark environment to prevent degradation.
Is this villiaumite?
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 villiaumite with a known reference. Villiaumite sits at Mohs 2-2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Villiaumite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Villiaumite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: carmine-red, pink, orange-red, colorless.
- 5Look at form & habitCrystal system: isometric. Typical habit: massive, granular, or rare cubic crystals.
Often confused with
Villiaumite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Fluorite is the harder of the two (Mohs 4 vs. 2-2.5).
How to tell apart: Streak differs — Villiaumite leaves white, Realgar leaves orange-red; luster reads vitreous on Villiaumite and resinous on Realgar.
Often found alongside villiaumite
Minerals reported to co-occur with villiaumite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaF
- Mohs hardness
- 2-2.5
- Density
- 2.79 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Isometric
- Crystal habit
- Massive, Granular, Or Rare Cubic Crystals
- Cleavage
- Perfect Cubic
- Fluorescence
- Orange Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Nepheline Syenite Pegmatites
- Typical price
- $50-500 thumbnail, $300-2000 cabinet specimen
Where rockhounds find villiaumite
Classic worldwide localities
- Mont Saint-Hilaire, Canada
- Kola Peninsula, Russia
- Los Islands, Guinea
Field-hunting tip
Look in nepheline syenite pegmatites country — that is the host setting where villiaumite typically forms. If you start seeing aegirine, microcline, sodalite in float, you are in the right ground. Field specimens usually show a massive, granular, or rare cubic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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How much is villiaumite worth?+
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Find villiaumite on the map
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