mineral

Dyed blue howlite or magnesite cabochon

Howlite (Ca₂B₅SiO₉(OH)₅), possibly magnesite (MgCO₃), artificially dyed blue

AI-generated identification · may be incorrect

Polished opaque blue cabochon with dark gray-black vein patterns; vitreous to waxy luster, white-to-gray streak, Mohs hardness about 3–3.5 (howlite) or 3.5–4.5 (magnesite), and no obvious cleavage visible. The intense blue color is likely dye rather than natural coloration.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Howlite forms as a borate mineral in evaporite-associated hydrothermal deposits, while magnesite forms by alteration of magnesium-rich rocks; both are generally Cenozoic or younger. This specimen has been cut, polished, and dyed for jewelry.

Uses & applications

Used for inexpensive beads, cabochons, carvings, and imitation turquoise; it has little value as an untreated mineral. Typical market value is about $2–$15 for a small cabochon, or $10–$40 in finished jewelry.

Geological facts

Dark web-like veins and vivid blue coloration commonly indicate “turquoise howlite,” a trade name rather than true turquoise. Dye may concentrate in cracks and can sometimes transfer to a solvent-moistened cotton swab.

Field identification & locations

Commonly found as white, porous, veined nodules from California, Nevada, and Canada; dyed examples are widely sold worldwide. Confirm with hardness, specific gravity, and non-destructive testing, since the photograph cannot distinguish howlite from magnesite confidently.