mineral

Tumbled blue stone, likely dyed howlite or magnesite

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

AI-generated identification · may be incorrect

Opaque vivid blue, smooth tumbled surface, waxy-to-vitreous luster; likely Mohs 3–3.5 (howlite) or 3.5–4.5 (magnesite). The visible material lacks diagnostic crystals or natural color zoning.

Identified August 25, 2026More mineral →

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Physical properties

Opaque vivid blue, smooth tumbled surface, waxy-to-vitreous luster; likely Mohs 3–3.5 (howlite) or 3.5–4.5 (magnesite). The visible material lacks diagnostic crystals or natural color zoning.

Formation & geological history

Howlite forms as a borate mineral in evaporite-associated deposits, while magnesite forms by alteration of magnesium-rich rocks; both are geologically young to ancient depending on deposit. The blue color and polish are human-applied.

Uses & applications

Commonly sold as inexpensive beads, cabochons, worry stones, and decorative tumbled stones; not generally used in construction. It is marketed as imitation turquoise or “blue howlite.”

Geological facts

Natural howlite is usually white with gray web-like veining, and magnesite is commonly white, gray, or tan; intense uniform blue strongly indicates dye. Dye often concentrates in surface fractures and pores.

Field identification & locations

Look for unnaturally saturated blue color, pale interior or fracture lines, and dye bleeding under solvent testing; avoid damaging tests on finished pieces. Common source regions include California and Nova Scotia for howlite, and many countries for magnesite.