Villiaumite Gemstone: Properties, Meanings, Value & More

Villiaumite is a deep red gemstone in the halide mineral family. This lesser-known stone is quite rare and mostly known among collectors, if at all.

Although villiaumite gemstones have been cut, they’re rare. The stone is soft and toxic, so jewelry uses are limited.

That’s not to say you should avoid villiaumite! With the proper knowledge, this gem makes a gorgeous addition to any collection.

You can get all that proper knowledge in this guide, where we’ll cover villiaumite’s mineral properties, history, uses, and prices, along with tips for handling the stone safely.

Pictured above: Complex villiaumite crystal specimen from Aris Quarries in Namibia | Image credit: Modris Baum, Public domain

About Villiaumite Stone

Villiaumite (pronounced vill-ee-AW-myte) is a rare semi-precious gemstone. It’s often deep carmine-red, but it can be brownish-red, lavender, pink, or orange.

This simple yet fascinating stone was first discovered in the islands of Guinea, off the coast of Western Africa.

Red villiaumite crystals are beneficial for the astrological fire signs: Aries, Leo, and Sagittarius. They can also substitute for ruby as a July birthstone or 40th wedding anniversary gem. However, villiaumites may be harder to find than rubies.

Villiaumite Uses

Villiaumite doesn’t have many industrial uses. Scientists have created synthetic villiaumites, but these aren’t on the gemstone or jewelry market.

Villiaumite also sometimes appears in scientific studies.

For instance, the Gemological Institute of America (GIA) reported in 1998 on a study conducted by the State Science Centre of Environmental Radiogeochemistry:

Villiaumite fluid inclusions in another (unnamed) mineral became brown when exposed to gamma radiation.

In a different 2023 study, researchers created a new ternary (three-part) eutectic salt composed of a carbonitic-villiaumite mixture with the formula K2CO3-Li2CO3-NaF.

The study presented methods for accurately calculating the enthalpy (heat energy) of eutectic salt (mixture melts without the components melting and mixing together).

Molten salts like the one in this study are important components in industrial thermal energy storage.

Pictured above: Outstanding large specimen from Russia featuring terminated villiaumite crystals in a cluster; Martin Zinn Collection | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Villiaumite Specifications & Characteristics

As a sodium fluoride mineral, the villiaumite formula is simple: NaF. Villiaumite is a halide mineral in the halite group. This group also includes sylvite, halite, griceite, and carobbite. All are isometric and almost all are fluorides, minus the potassium chloride sylvite.

Villiaumite is the sodium analogue of carobbite (potassium fluoride, or KF); conversely, carobbite is the potassium analogue of villiaumite.

Among halide minerals, the most well-known and commercially important (with many industrial uses) are fluorite and halite. Villiaumite joins minerals like halite and sylvite as a simple halide without water.

In terms of habits, villiaumite rarely forms crystals, but the ones that do form are small, cubic, and commonly rounded. More often, villiaumite occurs as granular masses.

Villiaumite Identification

Identifying villiaumite requires caution and expertise. The most common test is measuring villiaumite’s refractive indices (1.327 to 1.328), which are considerably low, even lower than that of water (1.333).

But this test shouldn’t be done with a refractometer because that requires villiaumite being in contact with liquids, which is dangerous.

Instead, gemologists can use the Duc de Chaulnes (or “Direct Measurement”) method, where you divide the gem’s physical “real” depth to its “apparent depth” with a mm-scale microscope.

Another possible test is for anomalous double refraction (ADR), present in some villiaumites, done with tools like a polariscope or dichroscope.

Here are villiaumite’s properties listed:

• Mohs hardness: 2-2.5

• Color: Carmine-red, brownish-red, dark red, lavender-pink, pink, light orange, orange; Colorless upon heating

• Crystal structure: Isometric (cubic)

• Luster: Vitreous (glassy)

• Transparency: Translucent to transparent; Opaque once cooled after heating

• Refractive index: 1.327-1.382; Material from Guinea - 1.330-1.332

• Density: 2.79

• Cleavage: Perfect on {001}

• Fracture: Uneven/irregular

• Streak: White or pinkish-white

• Luminescence: Fluorescence sometimes present - dark red, orange-red, orange-yellow, or yellow in SW-UV & LW-UV; Strong thermoluminescence when heated

• Pleochroism: Anomalous but present & strong in yellow to pink or deep carmine-red

• Birefringence: Technically none, but sometimes anomalous

• Dispersion: None

Pictured above: Villiaumite from Russia. On display at the San Diego County Fair, California, USA | Image credit: Stickpen, Public domain

Villiaumite History

French mineralogist and geologist Antoine François Alfred Lacroix published the first description of villiaumite in 1908. The original specimens were from Rouma Island, part of Los Islands (Archipelagos) in Guinea.

The name “villiaumite” honors Maxime Villiaume, a French explorer and colonial artillery corps officer stationed in Madagascar who helped get specimens from Madagascar and Guinea for Lacroix.

In 1976, the first facetable villiaumites were found elsewhere in Los Islands.

Villiaumite was discovered in Russia in 1982, Canada in 1989, and Namibia in 1992. These remain the only sources (outside of Guinea) for facetable villiaumites.

Villiaumite Healing Properties

As a red healing stone, villiaumite’s metaphysical properties match those of other red gemstones: offering vitality, energy, and motivation while also opening the root chakra.

Note: Do NOT put villiaumite into any crystal healing elixirs of any kind.

Physical Healing

Physically, villiaumite is believed to treat issues related to:

• Blood (circulation, disorders, iron levels)

• Immune system function

• Respiratory health

• Digestion

Emotional Healing

Emotionally, crystal healers recommend villiaumite crystals for:

• Facilitating inner peace

• Providing serenity

• Decreasing stress

• Diminishing depression

• Increasing feelings of self-worth

• Promoting optimism

Pictured above: Single, loose, gem-quality villiaumite crystal from Aris Quarries in Namibia | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Villiaumite Gemstone Properties

Besides its rarity, villiaumite’s value also depends on its color, cut, clarity, carat weight, and treatments.

Color

Most villiaumite gemstone material is carmine, a deep red with a subtle purple undertone but redder than crimson. (Other terms for carmine are cochineal extract, after the pigment made from crushed cochineal bugs).

Villiaumite can also be brownish-red, light orange, pink, or lavender-pink. Rarely, orange villiaumite resembles spessartine garnets.

Heating villiaumite to 300°C (572°F) makes them colorless. When cooled, it becomes opaque and white.

Why is villiaumite usually red? A 2021 study showed that the metal sodium nanoparticles affect the absorption band and coloring of both villiaumite and halite.

In villiaumite, the peak absorption is 512 nm, creating red coloring, while halite’s peak absorption is 372 nm, creating blue coloring.

Cut

Villiaumite’s low hardness and toxicity makes faceting the stone difficult. The villiaumite gems that have been faceted often have custom or freeform cuts.

More often, you’ll find the stone carved (like villiaumite spheres), cut into cabochons, or sold rough (uncut).

Clarity

Given villiaumite’s rarity, clarity (the degree of visible inclusions) doesn’t affect its value much. However, thorium-rich inclusions may cause irradiation of villiaumite.

The only other known inclusions in villiaumite are fluid inclusions.

Carat Weight & Size

The best villiaumite gemstone material comes from Guinea but only yields gemstones weighing 2 carats or less.

Facetable material from Canada, Russia, and Namibia has yielded larger gemstones (e.g. a 12.1-carat cabochon and 4.49-carat faceted villiaumite from Quebec; a 3.48-carat faceted villiaumite from Russia) but they’re not as high-quality as the ones from Guinea.

Villiaumite crystals are up to 15 cm (5.91 in) long.

Treatments

Villiaumite has been found to turn colorless upon heating and brown upon exposure to gamma radiation, both of which were mentioned earlier.

However, these treatments probably wouldn’t be done to make a villiaumite gem more desirable.

Pictured above: 10mm villiaumite crystal from Aris Quarries in Namibia | Image credit: Leon Hypperichs, CC-BY-SA-3.0

Villiaumite Formation & Sources

Villiaumite is found in alkalic (basic) rocks like nepheline syenites, nepheline syenite pegmatites, and occasionally phonolites. Sometimes, it’s found in salt lakebed deposits.

Thorium-rich nano-inclusions are found in villiaumites that formed in specific peralkaline rocks, and these inclusions help geologists understand the rocks’ geochemistry.

Minerals commonly associated with villiaumite are:

• Aegirine

• Chkalovite

• Ellingsenite

• Eudialyte

• Fluorite

• Lamprophyllite

• Microcline

• Natrolite

• Nepheline

• Neptunite

• Pectolite

• Serandite

• Sodalite

• Sphalerite

• Thermonatrite

• Tuperssuatsiaite

• Ussingite

• Zeolites

Geographically, where is villiaumite found?

Mining Locations

The best source of facetable villiaumite material is the original source: Los Islands in Guinea, particularly Rouma Island.

Other sources of facetable villiaumite material are:

• Canada (Quebec)

• Namibia

• Russia

The mineral is also found in:

• Brazil

• Greenland

• Italy

• Kenya

• Norway

• Poland

• Tanzania

• USA (Colorado, New Mexico)

Pictured above: Outstanding large specimen featuring gemmy, terminated, cherry-red villiaumite crystal | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Villiaumite Price & Value

Unsurprisingly, faceted villiaumite gemstones are usually the priciest.

Faceted villiaumites range from about $1,000 to $3,500 per carat or higher. However, the total prices are usually around $175 to $570 because the gems are under 1 carat.

Large carved villiaumite spheres are generally $600 to $1,250 or about $0.30 to $1 per carat.

Rough villiaumite crystals range from about $20 to $490 depending on their quality and size.

Villiaumite Care & Safety

Villiaumite has a very low softness and perfect cleavage, so gentle gemstone care is essential. Be sure to store the stone away from other gems or minerals to avoid scratches — even a fingernail may scratch villiaumite.

Additionally, villiaumite is heat-sensitive, so keep it away from direct sunlight.

We recommend avoiding jewelry use. Only keep villiaumite for display or collection.

Villiaumite Safety

A huge factor in owning this stone is knowing about villiaumite toxicity.

Why is villiaumite toxic? Its sodium fluoride composition and solubility in water. Sodium fluoride (the fluoride ion particularly) is highly toxic if ingested or inhaled. It’s even more toxic if it’s dissolved in water, which the human body absorbs more easily.

As such, gem cutters need to be extremely cautious and take serious precautions before cutting villiaumite.

If you’re not cutting villiaumite, still follow these tips:

1. Handle it with gloves or wash your hands thoroughly immediately after handling it

2. For extra protection, wear a mask to avoid inhaling particles that are easily scratched off the stone

3. Keep villiaumite away from pets or children

4. Don’t put villiaumite near your mouth or eyes

Remember: crystallized sodium fluoride used to be used in rat poison, so handle this mineral with care.

Villiaumite: A Valuable, Luxurious Jewel for Your Collection!

Villiaumite may be intimidating, but this gorgeous red gemstone is worth the safety precautions! It’s glassy, deep red appearance and alluring rarity make it a staple for a complete gem collection.

Buy villiaumite and other alluring gemstones today!