mineral
Dyed blue howlite or magnesite cabochon
Howlite (Ca₂B₅SiO₉(OH)₅), possibly magnesite (MgCO₃), artificially dyed blue
AI-generated identification · may be incorrectPolished 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.
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Physical properties
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.
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.
