mineral
Howlite
Hydrated sodium calcium borosilicate / Ca2B5SiO9(OH)5
AI-generated identification · may be incorrectMohs hardness of 3.5, white or yellowish color with distinct dark grey or black web-like veins, sub-vitreous to earthy luster, and monoclinic crystal system.
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Physical properties
Mohs hardness of 3.5, white or yellowish color with distinct dark grey or black web-like veins, sub-vitreous to earthy luster, and monoclinic crystal system.
Formation & geological history
Formed as borate minerals in evaporite deposits, typically in playa lakes, through the evaporation of boron-rich waters.
Uses & applications
Commonly used for ornamental carvings, beads, and often dyed blue to imitate turquoise in affordable jewelry.
Geological facts
First discovered in Nova Scotia in 1868 by Canadian chemist Henry How, it is exceptionally porous and accepts dyes very easily.
Field identification & locations
Easily identified by its characteristic chalky white appearance, webbed matrix, and softness that allows it to be easily scratched by a copper coin. Found notably in Nova Scotia, California, and South Africa.
