gemstone
Tanzanite
Zoisite (Ca2Al3(SiO4)(Si2O7)O(OH))
Hardness: 6-7 on the Mohs scale; Color: Blue, violet, purple, and brownish; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Cleavage: Perfect in one direction; Specific gravity: 3.10-3.38
- Hardness
- 6-7 on the Mohs scale
- Color
- Blue, violet, purple, and brownish
- Luster
- Vitreous to pearly
Identified More gemstone →
Explore Tanzanite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 on the Mohs scale; Color: Blue, violet, purple, and brownish; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Cleavage: Perfect in one direction; Specific gravity: 3.10-3.38
Formation & geological history
Formed through complex regional metamorphism in metamorphic rocks, typically found in hydrothermal veins and pegmatites. Formed approximately 585 million years ago during the Neoproterozoic era.
Uses & applications
Primarily used as a precious gemstone in fine jewelry such as rings, necklaces, and earrings. Highly valued by collectors.
Geological facts
Tanzanite is a rare gemstone found exclusively in one small mining area near the Merelani Hills in Northern Tanzania. It exhibits strong trichroism, showing different colors (blue, violet, and burgundy) when viewed from different crystal angles.
Field identification & locations
Easily identified by its characteristic rich blue-violet pleochroism and occurrence in metamorphic rock matrices. Found almost exclusively in Tanzania.
More like this
Other gemstone specimens
Gemstone Ring
N/A - Set piece of jewelry, likely Amethyst or Garnet with Diamond or CZ
gemstone
Diamond and Gold Jewelry
Carbon (Diamond) / Au (Gold)
gemstone
Ammolite
Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)
mineral
Cubic Zirconia (simulant) or Diamond
ZrO2 (Cubic Zirconia) or C (Diamond)
gemstone
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Black Opal Ring (Carved Opal)
Hydrated Silicon Dioxide (SiO2·nH2O)
gemstone