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)
orthorhombicrareSilicates
Tanzanite
Ca2Al3(SiO4)(Si2O7)O(OH)
This specimen displays a vibrant blue-violet to purplish-blue crystal of Tanzanite, a variety of zoisite, with a characteristic vitreous luster.
Tanzanite Physical Properties
Mohs Hardness
6.5Crystal System
orthorhombicLuster
vitreousStreak Color
whiteCleavage
perfect on {010}Fracture
unevenSpecific Gravity
3.15Colors
blue, violet, purplish-blueTransparency
transparentType Locality
Merelani Hills (Mererani), Lelatema Mts, Arusha Region, TanzaniaMineral Group
SilicatesUses
jewelry, collectorAssociated Minerals
graphite, diopside, tremolite, quartz, calcite, pyriteRarity
rareGeological Context
Tanzanite forms in regionally metamorphosed rocks, specifically within graphitic gneisses and schists, often associated with pegmatitic veins. Its unique color is attributed to vanadium impurities that are heat-treated.
