mineral
Howlite
Ca2B5SiO9(OH)5
AI-generated identification · may be incorrectHardness is 3.5 on the Mohs scale, color is white or milky with dark grey or black spiderweb veins, luster is vitreous to sub-earthy, and it has a monoclinic crystal system with no cleavage.
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Physical properties
Hardness is 3.5 on the Mohs scale, color is white or milky with dark grey or black spiderweb veins, luster is vitreous to sub-earthy, and it has a monoclinic crystal system with no cleavage.
Formation & geological history
Forms in evaporite deposits, primarily in borate-rich saline lakes and playas through chemical precipitation.
Uses & applications
Widely used as a polished gemstone for jewelry, beads, and carvings, and often dyed blue to imitate turquoise.
Geological facts
Howlite is frequently chalky and porous, which allows it to absorb dyes exceptionally well.
Field identification & locations
Identified by its soft Mohs hardness, white matrix, and distinct dark veining; major deposits are found in Nova Scotia and California.
