Howlite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameHowlite
Chemical FormulaCa₂B₅SiO₉(OH)₅
Mohs Hardness3.5
Crystal Systemmonoclinic
Lusterdull
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.53
Colorswhite, gray, brown
Transparencyopaque
Type LocalityWentworth area, Hants County, Nova Scotia, Canada
Mineral Groupborates
Usesjewelry, ornamental, carvings, collector
Associated Mineralsgypsum, calcite, other borates
Rarityuncommon
Description
A white to gray mineral, often characterized by distinctive gray or black veining, forming irregular nodules or massive aggregates. The image displays a white, nodular specimen with fine, dark gray veins.
Geological Context
Howlite forms as a secondary mineral in evaporite deposits and borate-rich sediments, often associated with volcanic activity. It typically occurs in massive, nodular forms within these environments.
