mineral

White Howlite

Howlite (Calcium borosilicate hydroxide, Ca2B5SiO9(OH)5)

Hardness: 3.5, Color: Milky white with black or grey veining, Luster: Sub-vitreous to dull, Crystal Structure: Monoclinic, Cleavage: None

Hardness: 3

Identified June 16, 2026More mineral →

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Physical properties

Hardness: 3.5, Color: Milky white with black or grey veining, Luster: Sub-vitreous to dull, Crystal Structure: Monoclinic, Cleavage: None

Formation & geological history

Formed in evaporite deposits in arid environments, often associated with gypsum or borax. Typically found in nodules resembling cauliflower.

Uses & applications

Commonly used as a gemstone for jewelry, beads, and decorative carvings; frequently dyed to imitate turquoise.

Geological facts

Named after Henry How, the Canadian mineralogist who first described it in 1868. It is extremely porous, making it the most common material used to create fake dyed turquoise.

Field identification & locations

Identify by its white porcelain-like appearance and irregular grey 'spider-web' veining. It is much softer than quartz or true turquoise. Found mostly in Nova Scotia, Canada, and California, USA.

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Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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Metamorphic Rock

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mineral