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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless, dark red, orange brown, pink.
- 5Look at form & habitCrystal system: cubic. Typical habit: granular, massive.
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, so Villiaumite leaves white, Realgar leaves red-orange to red; luster reads vitreous on Villiaumite and resinous to greasy 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
- Cubic
- Crystal habit
- Granular, massive
- Cleavage
- {001}, perfect
- Fluorescence
- Red under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In nepheline syenite and nepheline syenite pegmatites; in lake-bed deposits
Where rockhounds find villiaumite
Classic worldwide localities
- Point of Rocks, Colfax Co., New Mexico, and on Porphyry Mountain, Jamestown district, Boulder Co., Colorado, USA
- Rouma Isle, Los Islands, Guinea
- Mts. Karnasurt and Alluaiv, Lovozero massif, and from the Khibiny massif, Kola Peninsula, Russia
- Kvanefjeld, Ilímaussaq intrusion, Greenland
- Aris, about 20 km south of Windhoek, Namibia
- Lake Magadi, Kenya
Field-hunting tip
Where it forms: In nepheline syenite and nepheline syenite pegmatites; in lake-bed deposits. If you start seeing aegirine, sodalite, nepheline in float, you are in the right ground. Typical habit: granular, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify villiaumite?+
Where is villiaumite found?+
Is villiaumite safe to handle?+
What rocks look like villiaumite?+
What minerals are found with villiaumite?+
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Find villiaumite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
