mineral

Dyed blue howlite or magnesite (tumbled stone)

Howlite: Ca₂B₅SiO₉(OH)₅; commonly sold dyed blue to imitate turquoise

AI-generated identification · may be incorrect

Typically white, opaque, porous, and chalky with gray veining; this polished specimen is vivid blue with black-gray matrix lines and a vitreous-to-waxy luster. Mohs hardness 3–3.5; monoclinic crystal system, generally massive rather than visibly crystalline; specific gravity about 2.5–2.6.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Howlite forms as a borate mineral in evaporite-related hydrothermal deposits, commonly in arid sedimentary basins. Natural deposits are geologically young relative to many rocks, notably in California and Nova Scotia; the blue color is artificial dyeing.

Uses & applications

Used as inexpensive beads, cabochons, carvings, and tumbled stones; dyed material is marketed as “turquoise,” though it is not turquoise. Typical value is about $2–$15 for a small tumbled piece, or $10–$40 for larger polished specimens.

Geological facts

The strong blue color and dark vein pattern strongly suggest dyed howlite or magnesite rather than natural turquoise. Dye often concentrates in cracks and may bleed with acetone or alcohol, though testing can damage the finish.

Field identification & locations

Identify by unusually vivid, uniform blue color, low hardness, white interior beneath scratches, and porous gray veining; natural turquoise is usually denser and harder (Mohs 5–6). Common sources include California, Nevada, and Mexico.