Howlite
Image: Didier Descouens (CC BY-SA 4.0)
Mineral NameHowlite
Chemical FormulaCa₂B₅SiO₉(OH)₅
Mohs Hardness3.5
Crystal Systemmonoclinic
Streak Colorwhite
Cleavagepoor/indistinct on {100}
Fractureuneven to conchoidal
Specific Gravity2.53
Colorswhite, gray, brown, colorless, blue (dyed)
Transparencyopaque to translucent
Type LocalityTick Canyon, Lang, Los Angeles Co., California, USA.
Mineral Groupborates
Usesjewelry (often dyed), carvings, ornamental stone, collector
Associated Mineralsborax, ulexite, colemanite, gypsum, calcite
Raritycommon
Description
This specimen of Howlite is artificially dyed a vibrant turquoise blue, featuring a rough, nodular texture with prominent dark gray to black matrix veins creating a spiderweb pattern.
Geological Context
Howlite forms as nodules in evaporite deposits, often associated with other borate minerals. It is a secondary mineral resulting from the alteration of primary borates.
