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monoclinicuncommonBorates
Howlite
Ca₂B₅SiO₉(OH)₅
Howlite is typically a white to grayish-white mineral, often characterized by distinctive gray or black spiderweb-like veining. It commonly forms in nodular masses or as small, monoclinic crystals.
Howlite Physical Properties
Mohs Hardness
3.5Crystal System
monoclinicLuster
vitreousStreak Color
whiteCleavage
noneFracture
unevenSpecific Gravity
2.58Colors
white, grayish-whiteTransparency
opaqueType Locality
Nova Scotia (Canada), California (USA), Mexico, TurkeyMineral Group
BoratesUses
jewelry, carvings, decorative stone, collectorAssociated Minerals
colemanite, ulexite, gypsum, calciteRarity
uncommonGeological Context
Howlite forms as a secondary mineral in evaporite deposits, particularly in arid regions where borate-rich brines are present. It is often found in association with other borate minerals.
