Howlite

Howlite is a fascinating and somewhat notorious mineral in the world of gemology. While it is a distinct, naturally occurring calcium borosilicate hydroxide mineral with its own unique properties, it is far more famous for its ability to convincingly impersonate other, much more expensive gemstones—most notably turquoise. Its stark white base color, distinctive dark veining, extreme porosity, and affordability make it the most widely used dye substrate in the entire gemstone industry, contributing to confusion and deception in countless gift shops, markets, and online stores worldwide.

Discovery and History

The mineral was first discovered in 1868 near Windsor, Nova Scotia, Canada. Miners working in a gypsum quarry encountered a strange, harder material interfering with their extraction and brought it to Henry How (1828–1879), a local physician, chemist, and geologist. How identified it as a new calcium borosilicate hydroxide mineral and published a description in 1868, originally naming it “silicoborocalcite.” It was later renamed “howlite” in his honor by the prominent American mineralogist James Dwight Dana.

Formation and Geology

Howlite is primarily an evaporite mineral—it forms in arid environments where saline lakes or inland seas have partially or completely evaporated, leaving behind concentrated minerals. As borate-rich brines evaporate, howlite co-precipitates with gypsum, anhydrite, and other borates such as colemanite, ulexite, and borax. The mineral occurs almost exclusively as irregularly shaped nodules within massive gypsum deposits.

These nodules range from marble-sized to enormous boulders weighing hundreds of kilograms. Because howlite forms as an opaque, massive aggregate rather than as distinct crystals, the mineral is always encountered in massive form—the only known occurrence of microscopic crystals was at the original Nova Scotia locality.

The most commercially significant howlite deposits are in California’s Mojave Desert (Kern County) and in the borate mining regions of Turkey and China. The California deposit at Lang, in the Tick Canyon area, produced large nodules that became the foundation of the American lapidary howlite trade.

Physical Properties

In its natural state, howlite is an opaque, porcelain-white to milky-white mineral. Its most distinguishing visual feature is the presence of striking web-like veins or matrix in black, brown, or silver-gray tones running through the white material—an appearance startlingly similar to the matrix patterns in fine turquoise. This visual similarity, combined with howlite’s porosity, is what drives its widespread use as a turquoise substitute.

Physically, howlite has a hardness of only 3.5 to 4 on the Mohs scale—similar to copper or a fingernail. This softness makes it easy to cut, carve, and tumble polish, but means that jewelry made from howlite will scratch easily in everyday use. It has a slightly chalky to subvitreous luster and conchoidal to uneven fracture. The specific gravity is approximately 2.53–2.59.

The Porosity Factor

The single most commercially important physical property of howlite is its extreme porosity. Unlike denser minerals such as turquoise (which is itself porous), the interconnected microscopic pore structure of howlite nodules acts like a sponge—the stone absorbs liquids readily and retains them deeply and evenly throughout its mass. This property makes howlite the ideal substrate for artificial dyeing.

Howlite as an Imitation Stone

The gem trade’s relationship with dyed howlite is complex and widespread. By soaking howlite nodules in concentrated dye solutions, virtually any opaque stone can be convincingly replicated:

Turquoise Imitation: Dyed sky-blue or robin’s-egg blue, howlite with its natural black matrix resembles fine spiderweb turquoise almost perfectly. This is the most common use. Dyed howlite is sold in enormous quantities under many names: “turquenite,” “synthetic turquoise,” “craft turquoise,” and—most problematically—simply as “turquoise.”

Lapis Lazuli Imitation: Dyed deep blue and sometimes speckled with gold-colored pyrite dust, howlite is sold as “lapis howlite” or, deceptively, as lapis lazuli.

Coral Imitation: Dyed red or pink and carved into beads, howlite mimics red or pink coral.

Other Opaque Stones: Almost any opaque colored gem with matrix patterns can potentially be imitated by appropriately dyed howlite.

The deception ranges from outright fraud (selling dyed howlite as natural turquoise at turquoise prices) to legitimate commerce (clearly labeled “dyed howlite” or “stabilized turquoise simulant” sold for its aesthetic merit at appropriate prices). The problem is concentrated at the low-price end of the market—gift shops, tourist markets, and online retailers where undisclosed dyed howlite is sold as natural turquoise.

”White Turquoise”: The Deceptive Trade Name

A particularly misleading practice involves selling undyed white howlite as “White Turquoise.” While genuine white turquoise does exist—it is natural turquoise that contains little or no copper coloring agent—it is extremely rare and commands high prices. The term “white turquoise” applied to howlite exploits this confusion. White howlite is simply howlite, not turquoise of any color. Buyers who seek white turquoise should demand gemological documentation.

Testing for Howlite vs. Turquoise

Several tests distinguish howlite from natural turquoise:

Hot needle test: A heated needle touched to a dye-saturated area of dyed howlite releases the distinct smell of chemical dye; natural turquoise does not.

Acetone test: A cotton swab moistened with acetone wiped across dyed howlite will pick up color; natural turquoise color is not removed by acetone (though stabilized turquoise treatments may also react differently).

Specific gravity: Howlite (2.53–2.59) is lighter than most turquoise (2.60–2.90), but the difference is subtle without a precision scale.

Hardness: Howlite scratches with a copper coin; better-quality turquoise (5–6 Mohs) does not.

Gemological testing: Refractive index and absorption spectra differ; a gemological laboratory can definitively identify howlite.

Care for Howlite

Howlite requires careful handling. Its low hardness means it scratches easily—store away from other jewelry, avoid contact with rough surfaces, and take off howlite jewelry before physical activities. Keep dyed howlite away from prolonged water exposure (which can eventually leach dye), harsh chemicals, and strong cleaners. Clean with a barely damp soft cloth only. The porosity means that perfume, hairspray, skin oils, and lotions can penetrate and affect color over time; apply cosmetics before putting on howlite jewelry.

Natural White Howlite in Jewelry and Art

Setting aside its role as an imitation stone, natural white howlite has genuine aesthetic appeal. Its white porcelain appearance with intricate gray or black veining is visually interesting and unique. It carves easily, accepting fine detail for figurines and decorative objects. Unenhanced white howlite skulls, carvings, and beads are popular in collector and alternative jewelry markets.

Metaphysical Properties

In the crystal healing community, natural white howlite is highly regarded as an exceptionally calming stone—one of the most effective for stress reduction and emotional regulation. It is deeply associated with the crown chakra and the element of air. Practitioners use it primarily to absorb, neutralize, and dissipate anger, stress, and tension—both the wearer’s own and negative energy directed toward them. It is famously recommended to be placed under a pillow or kept on the nightstand to calm an overactive mind before sleep. Crystal healers also prize it for teaching patience, moderating impulsive behavior, and fostering calm, peaceful communication. In meditative practice, it is said to facilitate deep stillness and create a receptive, open state of awareness conducive to spiritual insight.

Natural howlite is also associated with memory, knowledge, and learning—believed to help the user absorb new information and retain it more effectively. Students and scholars in alternative wellness traditions sometimes keep howlite at their study spaces for this reason.