Ulexite Gemstone: Properties, Meanings, Value & More

Ulexite is a rare, lesser-known mineral that’s popular among collectors for its special optical abilities. Another name for ulexite is “television stone” or “TV rock” — though it’s a mineral, not a rock — for its ability to reflect images underneath it onto its surface.

Is ulexite a gemstone? It can be used as a gemstone, particularly specimens that display chatoyancy (the “cat’s eye” effect). However, it’s too fragile for jewelry use.

Here at Gem Rock Auctions, we’ve spent years in the industry learning about all stones, from fan favorites to underdogs.

In this guide, we’ll go over all of ulexite’s properties, history, benefits, and prices. Let’s crack in!

What Is Ulexite Stone?

Ulexite is a commonly colorless to white semi-precious gemstone with many monikers. Besides “television stone,” some of ulexite’s nicknames include:

• Cotton-ball borax

• Franklandite

• Hayesine / Hayesite

• Raphite

• Stiberite

• Tinkalzit

• Cryptomorphite

• Boronatro-calcite

• Natronborocalcite / Natroborocalcite

• Borocalcite

• Hydrous borate of lime

Astrologically, ulexite benefits those born under Gemini.

Ulexite can also imitate other stones. Its resemblance to clear quartz makes it an alternative April birthstone and 10th wedding anniversary gemstone.

In spring 2006, the Gemological Institute of America (GIA) reported on a simulant for cat’s eye chrysoberyl created by forming a triplet composed of ulexite surrounded by a synthetic yellow corundum dome.

Image credit: Rock Currier | Creative Commons Attribution 3.0 Unported license

Ulexite Specifications & Characteristics

As a hydrated sodium calcium borate, ulexite’s formula can be written a few ways:

• NaCaB5O95H2O or

• NaCa[B5O6(OH)6]·5H2O or

• NaCaB5O6(OH)6.5H2O

The last formula is the one accepted by the International Mineralogical Association (IMA).

Other hydrous borate minerals include colemanite, borax, and kernite. Like borax and colemanite, ulexite also technically classifies as a salt.

As far as magnetism, ulexite is not magnetic. Ulexite is also not piezoelectric, unlike the borate mineral boracite.

Usually, ulexite occurs as masses that may be lens-like, nodular, or rounded. Small rounded ulexite masses that are loose are often called “cotton balls.” Some ulexite specimens even resemble clam shells, fittingly nicknamed “clam shell” ulexite.

Ulexite crystals are rarer but can form stunning arrays of needle-like fibers radiating from a central point or pointing in random directions. Distinct crystals, even rarer, are often elongated.

Polysynthetic twinning on {010} and {100} is seen parallel to the elongated side of ulexite crystals.

Here are ulexite’s properties listed:

• Mohs hardness: 1-2.5

• Color: Colorless, white, gray

• Crystal structure: Triclinic

• Luster: Vitreous (glassy) or silky; May be vitreous on cleavage piece ends and silky on sides or vitreous on distinct crystals and silky to satiny on masses

• Transparency: Transparent to translucent

• Refractive index: 1.491-1.520

• Density: 1.650-1.955

• Cleavage: Perfect on {010}; Good/Imperfect to Poor/Weak on {110}

• Fracture: Uneven/irregular (across fibers)

• Streak: White

• Luminescence: Fluorescence & phosphorescence sometimes present; Yellow, greenish-yellow, green, blue-green, cream, or white in SW-UV

• Pleochroism: None

• Birefringence: 0.023-0.029

• Dispersion: None

• Optical effects: Possible chatoyancy

Image credit: Anders Sandberg, Flickr

Ulexite Meaning & History

Unsurprisingly, ulexite’s spiritual meaning ties into its physical properties. Ulexite is a stone of visualization and imagery, whether that means inspiring imaginative ideas or inducing psychic visions of other dimensions.

It’s also said to help you interpret your dreams and understand your spiritual path.

First References to Ulexite

Remember all those monikers from earlier? Well, this mineral went by many names before “ulexite” came along.

American chemist Augustus Allen Hayes made the first documented reference of ulexite in 1844, when he called it “hydrous borate of lime” in the American Journal of Science. He credited J.H. Blake for finding the specimens in the Iquique Province of Tarapacá, Chile, which is now the type locality.

Also in 1844, American mineralogist Francis Alger and English geologist William Phillips published a report on “borocalcite” which may have been ulexite or larderellite. Alger also reported on ulexite in 1844 under the name “hayesine” to honor Hayes.

Other subsequent names were:

• Hydroborocalcite: Used in 1847 by German mineralogist Johann Friedrich Ludwig Hausmann

• Boronatro-calcite: Given in 1849 by German chemist & politician Georg Ludwig Ulex, who wrote the first accurate chemical analysis of the mineral

• Natro-boro-calcite: First used in 1857 by British-Canadian chemist & geologist Henry How for specimens in Nova Scotia, Canada; Determined to be ulexite in 1975 by Vladimir Stephen Papezik & C.C.K. Fong

• Tinkalsite: Given in 1859 by Austrian chemist Vincenz Kletzinsky (or Kletzinski), after the term tinkal for impure borax

• Cryptomorphite: Used in 1861 by Henry How for another Nova Scotia specimen, possibly ulexite or ginorite

• Franklandite: Given in 1877 by Irish chemist James Emerson Reynolds, honoring Edward Frankland, for an alkali-rich ulexite

The name “ulexite” didn’t catch on until around 1918.

Later Discoveries About Ulexite

The “TV stone” nickname didn’t come until 1956, when John Marmon noticed the optical property in fibrous ulexite aggregates. This characteristic is typically seen in synthetic fibers, not minerals.

The mechanisms behind this characteristic were first explained in 1963 by American crystallographer Elizabeth Weichel Moore and Robert J. Potter, the first American to get a doctorate in fiber optics.

The crystallography of ulexite was first explored by American mineralogist Joseph Murdoch in 1940, re-examined by American geologists Joan R. Clark and C. Louis Christ in 1959, and finally described correctly in 1964 by Clark and American crystallographer Daniel E. Appleman.

Richard Maxwell Pearl coined the nickname “cotton ball borax” in 1964.

In 1991, American geologist George Donald Garlick first noticed another interesting characteristic: ulexite’s ability to display concentric circles of light when held up to a bright light or shining a laser pointer at an oblique angle through the stone.

Ulexite has plenty of history, but are there any metaphysical properties or beliefs associated with ulexite? You bet!

Pictured above: Translucent, polished ulexite stone from California showing "tv stone" effect | Image credit: James St. John, Flickr, CC-BY-SA-2.0

Ulexite Healing Properties

As a white healing stone, ulexite possesses the purifying and clarifying properties of other white gemstones. But its healing powers don’t end there!

Physical Healing

Physically, ulexite is said to treat or help with:

• Eyesight issues

• Headaches

• Nervous system function

• Memory loss

• Difficulties focusing

Emotional Healing

According to crystal healers, ulexite gemstone benefits include boosting creativity, helping you think for yourself, and assisting in problem-solving. For students or those in highly intellectual jobs, ulexite is believed to help you process complex ideas and remember them.

Spiritually, ulexite is a stone for assisting in visualization and revelation. Crystal healers recommend it for clarifying and manifesting your desires.

Chakra Healing

In energy healing (targeting blockages in energy centers called chakras), ulexite is a powerful third eye and crown chakra stone.

The third eye chakra controls our self-awareness and understanding of the world. The crown chakra represents spirituality and connection to higher powers. When both are opened with ulexite, you yourself are opened to greater awareness and connection to both yourself and the universe.

Outside of healing, what factors influence the pricing and valuation of ulexite gemstones in the market?

Ulexite Gemstone Properties

Though ulexite gemstones are rare, they’re still graded on standard properties like color, cut, clarity, and carat weight.

Color

Ulexite is only found in white, colorless, or gray hues. The best ulexite color is fully colorless and transparent or pearly white. Most ulexite stones are milky.

Cut

Ulexite is very rarely faceted, given its softness, perfect cleavage, and rarity. Some rare material may be faceted for collectors, like this 22.14-carat cushion-cut ulexite from GIA.

Fibrous specimens that display chatoyancy, the “cat’s eye” effect, must be cut as cabochons. Many ulexite specimens are sold uncut.

Clarity & Transparency

Clarity describes the visible inclusions in a gemstone. Fewer inclusions mean higher value in ulexite, as they can affect the transparency and thus, the “TV stone” effect.

Most ulexite crystals have black and white inclusions, helping distinguish them from the similar crystal selenite.

Carat Weight & Size

Larger ulexite stones of good quality can cost more, but you can find ulexite nodules weighing multiple pounds.

Speaking of finding ulexite, where is ulexite primarily found geographically, and what are its main mining locations?

Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Ulexite Formation & Sources

Borate minerals like ulexite are rare — since boron is rare — and usually only form in arid conditions, often areas where volcanism is common.

These minerals form when pyroclastic (fragmented) rocks leach solutions containing boron. The solutions run into basins and evaporation occurs, causing borate deposition in stratified layers.

Ulexite is usually found in evaporite deposits like salt playas and dry saline lakes. Playas are dry, flat areas at the bottom of undrained desert basins where water may briefly fill the area.

Occasionally, ulexite is found in fumaroles and hot springs.

The mineral is usually found with borax, colemanite, and other borate minerals.

Commonly associated minerals include:

• Borax

• Colemanite

• Hydroboracite

• Calcite

• Gypsum

• Halite

• Meyerhofferite

• Probertite

• Glauberite

• Trona

• Mirabilite

Mining Locations

The primary source of ulexite is Boron, California, USA.

Other significant sources are:

• Argentina

• Bolivia

• Chile

• Kazakhstan

• Nevada, USA

• Peru

• Russia

Most ulexite for industrial use is mined in Turkey and California (USA).

Image credit: Cran Cowan, Flickr

Ulexite Price & Value

Ulexite can be affordable, but its price varies by the form, size, and seller.

You can find small, clear ulexite crystals or slabs for under $10.

Large crystal specimens with attractive or rare habits (like radiating needle-like crystals) can cost upwards of $200.

Cat’s eye ulexite cabochons are usually $120 to $200 each or $25-$105 per carat.

Once you’ve bought it, what are some tips for caring for and preserving the beauty of ulexite specimens?

Ulexite Care and Maintenance

Before we discuss gemstone care, is ulexite poisonous? Ulexite is considered non-hazardous with low acute oral and dermal toxicity. It’s not flammable, explosive, or combustible.

If you’re curious, ulexite doesn’t have a taste, unlike the alkaline flavor of similar borate minerals.

Given its considerably low hardness and brittle nature, ulexite isn’t recommended for jewelry use.

You’ll want to keep ulexite away from water and household chemicals. It will decompose slightly in cold water but quicker in hot water.

Don’t use ultrasonic cleaners on ulexite. Store it in dry conditions separately from other gems.

Image credit: Brandon Cripps, Flickr

Frequently Asked Questions

Still have questions? Don’t worry, we’ve got you covered.

How does ulexite's unique optical property, known as "TV rock" effect, occur?

Ulexite’s “TV stone” quality is technically a fiber optic effect.

The reason for this fiber optic effect is because ulexite displays something called total internal reflection. That means light travels along the length of each fiber. Slow rays are internally reflected and fast rays are refracted, polarizing the light.

The same way glass fibers transmitted light signals to display images in early televisions, ulexite’s natural fibers allow you to see the reversed image of an object placed parallel beneath it.

The diameter of the fibers must be small to produce a sharp image — coarser fibers mean less sharp images.

You can see another neat optical effect by putting ulexite up to a bright light: it will produce concentric circles of light!

What are the primary uses of ulexite in industrial applications and lapidary arts?

In lapidary arts, ulexite is most often cut into cabochons. Some of these are placed into jewelry like pendants or rings.

Ulexite as a mineral isn’t rare, so you’ll mostly see ulexite used industrially.

Most of ulexite’s industrial uses come from its boron content. Boron is quite rare but important to many industries. In fact, ulexite is among the three most abundant sources of industrial boron, along with borax and colemanite.

Some uses for boron or boron compounds extracted from ulexite include:

• Fiberglass

• Heat-resistant & thermal shock-resistant borosilicate glass (e.g. Pyrex, headlights)

• Eye drops

• Soaps & detergents

• Tile & pottery glazes

• Glassmaking flux

• Epoxy composite filler (increases thermophysical properties)

• Medical imaging dyes

• Metal alloy production

• Fire retardants

• Metal hardener in military vehicles

• Fertilizer

• Pesticide / insecticide

• Wood preservation

Another benefit of ulexite is that it forms calcium carbonate (calcite) as a by-product after dissolving in a carbonate solution. This by-product can be used numerous ways, from coating and filling printer paper to relieving heartburn as an antacid.

Many researchers have found that ulexite has potential for helping battle climate change by:

1. Producing compounds for hydrogen energy storage: Researchers in 2009 showed ulexite could help synthesize sodium borohydride (NaBH4), a great medium for hydrogen storage (a cleaner energy source)

2. Decreasing carbon dioxide emission: Ulexite was shown in 2020 as useful in sequestering CO2 while producing trimethyl borate. In a 2024 study, carbonating ulexite ore waste also proved to be effective at reducing CO2 emissions from utility power plants.

3. Adsorption of Toxic Dyes: In a 2020 study, ulexite was shown to be potentially effective at removing the dye methyl orange (a common and toxic pollutant in industrial wastewater) from aqueous solutions

Ulexite continues to be studied for other important uses, like neutron and gamma radiation shielding in High-Density Polyethylene (HDPE) composites — an environmentally friendly plastic — and concretes.

Pictured above: Specimen from Boron, California, with radiating spray of ulexite needles associated with translucent, rounded masses of calcite crystals; Jim Minette Collection | Image credit: Rob Lavinsky, iRocks.com – CC-BY-SA-3.0

Are there any notable variations or color varieties of ulexite?

Ulexite doesn’t come in many colors — just white, colorless, or gray. However, ulexite does come in a few interesting habits:

• Fibrous — Long, thread-like crystals that may be parallel or oriented in different directions

• Nodule — Crystals forming rounded, often radial structure

• Acicular — Needle-like crystals

• Cotton ball — Small, rounded tufts of acicular crystals

• Clam shell — Fibrous crystals radiating outward in slightly irregular pattern, forming ridges and shape resembling a clam shell

• Botryoidal crust — Aggregate with many rounded or globular segments, resembling a cluster of grapes

• Filiform — Many acicular crystal filaments forming felt-like aggregates

These may even combine together. Many of ulexite’s habits include fibrous crystals that simply grow in different ways to form different aggregates or clusters.

What are the key characteristics and properties of ulexite gemstones?

The main properties that ulexite is distinguished by are:

• Optical Phenomena: Fiber optic (“TV stone”) abilities & sometimes chatoyancy (cat’s eye effect)

• Hardness: Very low scratch resistance at 1 to 2.5 on the Mohs scale

• Density: Pretty low density at 1.650-1.955

Additionally, miners can often identify ulexite by its presence in arid environments with a history of volcanism.

How can I distinguish genuine ulexite specimens from similar-looking minerals?

Despite the many mentions of calcite among ulexite’s monikers, ulexite is most often confused with selenite. Though they look similar, there are some key differences between ulexite vs selenite:

• Composition: Selenite is a variety of gypsum; ulexite is a borate mineral.

• Crystal Symmetry: Selenite is monoclinic; ulexite is triclinic.

• Rarity: Selenite is commonly seen as a gemstone; ulexite gemstones are rare.

• Density: Selenite has a higher density of 2.3-2.9; ulexite’s density is 1.65-1.95.

One type of selenite called satin spar can actually display a “TV stone” effect similar to ulexite, but its fibers are so coarse that the transmitted image isn’t very sharp.

Here are some other minerals similar to ulexite and how you can distinguish them:

• Probertite: Slightly higher hardness (3.5), monoclinic crystal symmetry, very rarely shows twinning

• Larderellite: Much rarer, only known from Larderella (Italy), monoclinic crystal symmetry

• Cat’s Eye Topaz: Much higher hardness (8), pleochroic, orthorhombic crystal symmetry, much higher density (3.49-3.57)

• Cat’s Eye Sillimanite: Higher hardness (6.5-7.5), orthorhombic crystal symmetry, often pleochroic, more variable colors

• Synthetic Fiber Optic Chatoyant Glass: (AKA “Catseyte” or “Cathaystone”) Man-made, sometimes displays a wavy band in cabochons, higher hardness (4.5-7), no crystal symmetry, usually conchoidal fracture

Last but not least...

Are there any famous or significant pieces featuring Ulexite gemstones?

Ulexite isn’t very well-known, so there aren’t many famous pieces of ulexite yet. However, you can find ulexite stones on display at renowned museums like the Smithsonian Museum of Natural History!

Uncover Your True Self with Ulexite!

Ulexite may not be a well-known gem, but its popularity has been increasing as of late. Collectors love its unique optical properties and gorgeous natural shapes, while crystal healers love its purported ability to help you understand and harness your true power.

Either way, ulexite doesn’t fail to impress!

Buy ulexite gemstones today!

Ulexite