Tanzanite
Variety Ca2Al3(SiO4)(Si2O7)O(OH)
Take care.
- Sensitive to heat: Keep it away from heat and sudden changes of temperature, including hot lights and ultrasonic cleaners.
About it
Violet-blue zoisite from one small area near Merelani, Tanzania; most is brownish when mined and heated to blue. It shows blue, violet, and bronze from different angles; avoid heat shock and ultrasonic cleaners.
- Type
- Variety
- Group
- Zoisite variety (epidote group)
- Formula
- Ca2Al3(SiO4)(Si2O7)O(OH)
- Hardness (Mohs)
- 6–7
- Specific gravity
- 3.15–3.38
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Orthorhombic
- Colours
- violet-blue, blue, purple
- Transparency
- transparent
- Cleavage and fracture
- perfect in one direction; uneven to conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.