Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
monoclinicuncommonborates
Howlite
Ca₂B₅SiO₉(OH)₅
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.
Howlite Physical Properties
Mohs Hardness
3.5Crystal System
monoclinicLuster
dullStreak Color
whiteCleavage
noneFracture
conchoidalSpecific Gravity
2.53Colors
white, gray, brownTransparency
opaqueType Locality
Wentworth area, Hants County, Nova Scotia, CanadaMineral Group
boratesUses
jewelry, ornamental, carvings, collectorAssociated Minerals
gypsum, calcite, other boratesRarity
uncommonGeological 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.
