How to clean it
Warm soapy water and a soft brush. No ultrasonic, no steam — tanzanite is sensitive to sudden temperature change.
Violet blue to deep purple
Tanzanite
The birthstone for December.
Is Tanzanite a birthstone?
Yes. Tanzanite is the modern birthstone for December.
Properties
Composition
Calcium aluminium silicate (Ca₂Al₃(SiO₄)₃(OH)) — blue zoisite
Hardness (Mohs)
6–7
Crystal system
Orthorhombic
Colour
Violet blue to deep purple
Mined in
Tanzania (Merelani Hills — the only source on Earth)
Worth knowing
Mined in a strip of land roughly seven kilometres long. At current rates the deposit is expected to run out within decades.
History
Found in 1967 and named by Tiffany & Co. the following year.
Practical
Caring for Tanzanite
How to tell it is real
Effectively all tanzanite is heat-treated to produce the blue; unheated material is brown and rare. Coated imitations exist and need a lab to separate.
One general rule covers most mistakes: never store stones loose together. Diamond at 10 on the Mohs scale scratches everything else you own, and it does not need much contact to do it.
What that hardness means in practice
Softer than household dust. Better in earrings or a pendant than in a ring, where it takes constant knocks.
Traditional associations
Tanzanite is traditionally linked to perspective shifts and seeing a situation from above. In chakra systems it is placed at the Third Eye, Crown, and in elemental correspondence it is assigned to Air.
These are cultural associations recorded across various traditions, not claims about physical effects. The composition and hardness above are measurable; this paragraph is folklore, and worth reading as such.
Questions
What is Tanzanite made of?
Calcium aluminium silicate (Ca₂Al₃(SiO₄)₃(OH)) — blue zoisite, crystallising in the orthorhombic system.
Which month is Tanzanite the birthstone for?
December.
Where does Tanzanite come from?
Tanzania (Merelani Hills — the only source on Earth).
How do I clean Tanzanite?
Warm soapy water and a soft brush. No ultrasonic, no steam — tanzanite is sensitive to sudden temperature change.
How can I tell if Tanzanite is real?
Effectively all tanzanite is heat-treated to produce the blue; unheated material is brown and rare. Coated imitations exist and need a lab to separate.
Can I wear it every day?
At 6–7 on the Mohs scale, not in a ring. Keep it to pieces that take fewer knocks.