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)
orthorhombicuncommonSilicates
Prehnite
Ca₂Al(AlSi₃O₁₀)(OH)₂
This specimen displays a pale green, botryoidal aggregate of Prehnite, exhibiting a translucent quality. The surface has a smooth, rounded appearance typical of its growth habit.
Prehnite Physical Properties
Mohs Hardness
6.5Crystal System
orthorhombicLuster
vitreousStreak Color
whiteCleavage
Good on {001}Fracture
unevenSpecific Gravity
2.9Colors
pale green, yellowish-green, white, grayTransparency
translucentType Locality
Merelani Hills (Mererani), Lelatema Mts, Arusha Region, TanzaniaMineral Group
SilicatesUses
jewelry, carvings, collector specimensAssociated Minerals
zeolites, apophyllite, calcite, epidote, copperRarity
uncommonGeological Context
Prehnite typically forms as a secondary mineral in veins and cavities of mafic igneous rocks like basalts and gabbros, often associated with low-grade metamorphic conditions. It can also be found in some metamorphic rocks.
