What is Tanzanite?


Tanzanite is a blue and violet variety of the mineral zoisite and is only found in Tanzania, in a very small mining area near the Merelani Hills. Tanzanite is a relatively new gemstone, having been discovered in 1967, and has gained immense popularity due to its rarity and stunning hue.

Tanzanite is a vibrant blue-violet gemstone that belongs to the zoisite family. Its unique color and rarity make it a popular choice for jewelry, especially rings and earrings.

Gemstone Properties

Chemical ClassificationInorganic - Silicate (Zoisite)
ColorTanzanite displays a range of colors from deep blue to vibrant violet. It can also exhibit pleochroism, showing different colors when viewed from different angles.
OccurrenceTanzania (specifically the Merelani Hills).
FormationTanzanite forms in metamorphic rocks, particularly in the presence of high amounts of vanadium.
Mohs Hardness6.5 to 7.
Specific Gravity3.35.
Diagnostic PropertiesBlue to violet, a variety of zoisite.
Chemical CompositionCa2Al3(SiO4)(Si2O7)O(OH)
PleochroismDistinct; tanzanite can display different colors (typically blue, violet, and burgundy) depending on the viewing angle.
Crystal SystemOrthorhombic (variety of Zoisite)
Optical PropertiesBiaxial (+)
Refractive Index1.691 - 1.700
Birefringence0.006 - 0.013
2V angleMeasured: 58° to 63°