Color:
Blue to purple, with shades of violet in between.
Gem family:
Zoisite
Birthstone:
December
History:
Has only one known source, the hills of Merelani in northern Tanzania. Initially believed to be a sapphire.
Use in jewelry:
Can be cut and faceted in a variety of shapes, making tanzanite a versatile gemstone for use in jewelry.
Mohs hardness:
6-7 (1 softest to 10 hardest)
Common treatments:
Most tanzanite is heated to improve color. All treatments must be disclosed.
Care:
Mild soap and warm water, dry with soft cloth. Never use ultrasonic or steam cleaners.