Tanzanite

Real mineral · very rare · Ca₂Al₃(SiO₄)₃(OH)

A blue-violet variety of zoisite found only in a small area near Mount Kilimanjaro. Its colour results from vanadium impurities. Displays strong trichroism, appearing blue, violet, or burgundy depending on viewing angle.

Identity

Formula
Ca₂Al₃(SiO₄)₃(OH)
Chemical class
silicate
Also known as
Blue zoisite

Crystallography

Crystal system
orthorhombic
Habits
prismatic, tabular
Fracture
conchoidal

Physical properties

Mohs hardness
6.5
Density
3.35 g/cm³
Luster
vitreous
Colors
blue, violet, purple
Streak
white
Transparency
transparent, translucent

Geology

Origins
metamorphic
Host rocks
gneiss, schist
Associated minerals
Corundum, tsavorite garnet, Graphite
Geography
Tanzania (Merelani Hills only)

Classification

Rarity
very rare
Gem quality
Yes

Arcane properties

Affinity
arcane, void
Effects
scrying, planar travel
Planar origin
Material Plane

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