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GEMSTONE LIBRARY

TANZANITE

Tanzanite is a blue to purple-blue variety of zoisite. This variety of zoisite is mined in Tanzania. The blue colour of the tanzanites can be achieved by heating brown-coloured zoisites.

Each gemstone brought to the laboratory is analysed and identified. With tanzanites, heat treatments can be detected, particularly through spectrometry.

CHARACTERISTICS

  • Name: Tanzanite
  • Mineralogical nature: Zoisite
  • Colour: Blue to purple
  • Crystal system: Orthorhombic
  • Chemical composition: Ca2Al3Si3O12(OH)
  • Causes of colour: V3+ and V4+
  • Density: 3.23 to 3.38
  • Hardness: 6 to 6,5
  • Cleavage: Clean {100}
  • Fracture: Conchoidal
  • Optic sign: Positive bias
  • Refractive index: np: 1.696 to 1.700 / nm: 1.696 to 1.702 / ng: 1.702 to 1.718
  • Birefringence: 0.006 to 0.009
  • Dispersion: 0.021
  • Pleochroism: Strong yellow-brown to blue to purple
  • UVL: Inert
  • UVC: Inert
  • Treatments: Thermal treatment
  • Syntheses: In a research laboratory
  • Geographical origin: Tanzania

CONTACT US :

contact-laboratoire@bjop.fr
01 40 26 25 45
30, rue Notre-Dame des Victoires - 75002 Paris
Monday - Thusday : 9H30 to 16H30
Friday : 9h30 to 15h30
Withdrawal files at same days and time

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