Tanzanite
Variety of zoisite
Very Rare · Ca₂Al₃(Si₂O₇)(SiO₄)O(OH)
A blue-violet variety of zoisite mined in only one place, the Merelani Hills of northern Tanzania, where it was found in 1967. Its colour comes from vanadium. Strongly trichroic: blue, red-violet and yellow-green by direction, and most stones are heated to remove the yellow-green and deepen the blue.
Identity
- Formula
- Ca₂Al₃(Si₂O₇)(SiO₄)O(OH)
- Chemical class
- Silicate
- Mineral group
- Epidote, Zoisite
- Also known as
- Blue zoisite
- Used in alchemy
- Tanzanite Powder
Crystallography
- Crystal system
- Orthorhombic
- Habits
- Prismatic, Columnar
- 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
- Schist and gneiss, Limestone and chalk
- Associated minerals
- Graphite, tsavorite garnet, Diopside, Quartz, Calcite
- 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
Sources
- Tanzanite. Mindat.org (Hudson Institute of Mineralogy).
- Zoisite. Mindat.org (Hudson Institute of Mineralogy).
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Zoisite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Tanzanite. Gemdat.org (Hudson Institute of Mineralogy).
- Tanzanite Description. Gemological Institute of America, Gem Encyclopedia.
- Merelani Hills, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania. mindat.org.
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