mineral

Dyed blue howlite or magnesite tumbled stone

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

AI-generated identification · may be incorrect

Typically white to gray with a porous, opaque texture and dark natural veining; the bright blue color is dye. Hardness is about 3–3.5 Mohs, vitreous to dull luster, and irregular fracture rather than prominent cleavage.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Howlite forms as a borate mineral in evaporite-related deposits, while magnesite forms through alteration of magnesium-rich rocks; both are geologically young to ancient depending on deposit. This specimen has been cut, polished, and dyed after formation.

Uses & applications

Sold as inexpensive ornamental beads, cabochons, and tumbled stones, often marketed misleadingly as “dyed turquoise.” Typical value is about $2–$10 per piece, or $10–$30 for a small polished lot.

Geological facts

The vivid electric-blue color and web-like dark pattern are characteristic of dyed howlite or magnesite, not natural turquoise. Dye may concentrate in pores and surface cracks.

Field identification & locations

Likely sources include California and Nevada for howlite and Austria, Brazil, or China for magnesite. Test cautiously: an inconspicuous acetone swab may remove dye; hardness and acid tests can help distinguish carbonate minerals, but may damage the specimen.