Tanzanite
Blue-violet zoisite from one hill in Tanzania, found in 1967.
- Family
- Zoisite
- Formula
- Ca₂Al₃(SiO₄)₃(OH)
- Mohs
- 6 to 7
- System
- Orthorhombic
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Science
Tanzanite is the vanadium-bearing variety of zoisite. It is strongly trichroic, showing blue, violet and burgundy along its three axes; heating to about 600 °C removes the brown and is applied to nearly every stone. Cutters choose between a bluer or more violet face-up colour at the expense of weight.
- Mineral
- Zoisite (variety)
- Formula
- Ca₂Al₃(SiO₄)₃(OH)
- Crystal system
- Orthorhombic
- Mohs hardness
- 6 to 7
- Specific gravity
- 3.35
- Refractive index
- 1.691 to 1.700
- Lustre
- Vitreous
- Colours
- Blue, Violet
- Birthstone
- December
Composition
Ca₂Al₃(SiO₄)₃(OH). Made of Calcium, Aluminium, Silicon, Oxygen, Hydrogen, with trace Vanadium responsible for colour.
Origin
- TanzaniaMerelani Hills, Manyara
Filled dots are primary sources
Rarity
A single deposit a few kilometres long. Estimates give it a few decades of remaining supply.
- 1 Abundant
- 2 Common
- 3 Uncommon
- 4 Rare
- 5 Exceptional
Hardness
Tanzanite sits at 6 to 7 on the Mohs scale. It will scratch glass and holds a polish in daily wear.
Energy
Associations from crystal-healing tradition, recorded here as folklore. They are not medical claims.
Chakras
- Third Eye
- Throat
- Crown
Element
- Air
Zodiac
- Sagittarius
- Gemini
- Pisces
Planets
- Neptune
Properties
- Insight
- Spiritual awakening
- Communication
- Transformation
Lore
A Maasai herder, Ali Juuyawatu, showed the crystals to prospector Manuel de Souza in 1967. Tiffany named the stone and launched it in 1968 as the new gem of the century.
Maasai tradition gives blue stones to women after childbirth; tanzanite has been folded into that custom.
- TrichroicThree colours from three directions, more than almost any gem.
- HeatStandard treatment; a 1960s bushfire is said to have revealed it.