mineral
Polished howlite bead
Howlite, a hydrous calcium borosilicate hydroxide: Ca₂B₅SiO₉(OH)₅
AI-generated identification · may be incorrectWhite to cream with gray-black veining; vitreous to dull luster, monoclinic structure, Mohs hardness 3.5. The spherical polished bead shows characteristic web-like veins, though the photo alone cannot confirm identity.
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Physical properties
White to cream with gray-black veining; vitreous to dull luster, monoclinic structure, Mohs hardness 3.5. The spherical polished bead shows characteristic web-like veins, though the photo alone cannot confirm identity.
Formation & geological history
Howlite forms in borate-rich evaporite deposits, commonly as nodules in arid sedimentary settings. It is a relatively young secondary mineral, but a specimen’s age cannot be determined visually.
Uses & applications
Carved and polished into beads, cabochons, and ornaments; often dyed to imitate turquoise. It has little industrial use.
Geological facts
Named for Canadian chemist Henry How, who described it in 1868. It is porous and readily accepts dye.
Field identification & locations
Look for a soft white body with irregular gray veining; it scratches more easily than turquoise. Major occurrences include California and Nova Scotia.
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