mineral
Howlite
Ca2B5SiO9(OH)5
AI-generated identification · may be incorrectMohs hardness of 3.5, white or milky color with dark grey to black web-like veins, sub-vitreous luster, and monoclinic crystal system.
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Physical properties
Mohs hardness of 3.5, white or milky color with dark grey to black web-like veins, sub-vitreous luster, and monoclinic crystal system.
Formation & geological history
Forms as nodular masses in evaporite deposits, primarily created through the alteration of gypsum and anhydrite in arid environments.
Uses & applications
Widely used in ornamental carvings, beads, and cabochons for jewelry, and often dyed blue to imitate turquoise.
Geological facts
Named after Henry How, the Canadian chemist who first discovered it in Nova Scotia in 1868. It is extremely porous and readily absorbs dyes.
Field identification & locations
Identified by its chalky white appearance, dark spiderweb matrix, and softness that allows it to be easily scratched by a knife.
