Howlite is a popular calcium borosilicate hydroxide mineral frequently used in jewelry and decorative objects due to its attractive appearance and affordability. Because it is a relatively soft and porous material, howlite is often altered or misrepresented in the marketplace. Verification of authenticity is necessary because the stone is frequently dyed to imitate more expensive materials like turquoise, or substituted with cheaper materials such as plastic or other minerals.
Understanding Howlite’s Natural Characteristics
Genuine howlite exhibits a distinctive appearance characterized by a chalky white or off-white base color and a matte luster. The surface is often traversed by fine, erratic, gray-to-black veins that create a spiderweb-like matrix pattern across the stone. These markings are caused by natural mineral inclusions and are typically irregular in thickness and distribution.
The physical properties of howlite offer the first clues to its identity, particularly its relatively low density. Howlite is chemically composed of calcium, boron, silicon, and oxygen, resulting in a material that feels noticeably lighter than a similar-sized piece of quartz or glass. The mineral is quite soft, registering approximately 3.5 on the Mohs scale of mineral hardness. This low hardness means the material is easily scratched and contributes to its porous nature, allowing it to readily accept dyes.
Identifying Common Imitations
One of the most frequent substitutions for howlite is magnesite, a magnesium carbonate mineral that shares a similar white color and veining potential. Magnesite is a harder and denser stone, registering between 4 and 4.5 on the Mohs scale. When dyed to mimic howlite, the veining in magnesite often appears thicker, more defined, and sometimes unnaturally uniform compared to the thin, irregular network found in genuine howlite.
Another common imitation involves synthetic materials such as plastic or resin, which are molded and painted to resemble the stone. These fakes often feel unnaturally warm to the touch, as plastic does not transfer heat away from the skin like genuine stone. Close inspection may reveal subtle mold lines or a glossy, artificial sheen inconsistent with the matte finish of natural howlite. Resin pieces also feel disproportionately light for their size.
The issue of artificially colored howlite is prevalent, often marketed as “blue howlite” or “turquoise howlite.” While the base material is genuine howlite, the vibrant color is achieved through dyeing. The porous nature of howlite allows the dye to soak in deeply, often concentrating and pooling visibly within the natural fissures and veins. Recognizing that these brightly colored varieties are chemically altered is important, as the color is not a natural characteristic of the mineral.
Practical Steps for Testing Authenticity
A simple test to check for artificial color involves applying a solvent to an inconspicuous area of the stone. A cotton swab dipped in acetone, such as nail polish remover, can be gently rubbed against the surface, ideally on the underside of a bead or setting. If the howlite has been dyed, the solvent will lift the color, causing the dye to transfer onto the cotton swab.
Evaluating the stone’s thermal properties and density helps distinguish it from plastic or heavier mineral substitutes like magnesite. Genuine howlite, like most natural stones, feels cool when first touched and takes time to warm up to body temperature. Comparing the stone’s mass to a known piece of plastic or glass of similar dimensions helps estimate its density. A stone that feels too light suggests plastic, while one that feels surprisingly heavy might indicate magnesite.
The relative softness of howlite allows for a cautious scratch test, though this should be a last resort as it can damage the specimen. If a steel point, such as a sewing needle tip, is lightly pressed against an inconspicuous area, a genuine howlite (Mohs hardness 3.5) could potentially be marked. Conversely, a material like magnesite (4-4.5) resists scratching more readily. Plastic reacts differently, often resulting in a gouge or deformation rather than a clean scratch.