Difference between revisions of "Tanzanite"

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{{Tanzanite}}
 
{{Tanzanite}}
Tanzanite, is a variety of [[zoisite]], discovered in the Merelani district of Tanzania, near Mount Kilimanjaro in 1967. So far, all tanzanite discovery has been limited to a six kilometer strip in this area, which was divided into four blocks, labeled A, B, C and D. Block C is the only site still commercially producing rough tanzanite at this time.
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Tanzanite, a variety of [[zoisite]], was discovered in the Merelani district of Tanzania near Mount Kilimanjaro in 1967. So far, all tanzanite discovery has been limited to a six kilometer strip in this area, which was divided into four blocks, labeled A, B, C and D. Block C is the only site still commercially producing rough tanzanite at this time.
  
All purple and blue varieties of the stone are the result of heat treatment. The stone is a yellowish-brown "bug juice" color when it is mined, but when heated to between 800-900 degrees Fahrenheit, it becomes that gorgeous violet blue that is used in jewelry. The stone has never been found in another locality, so it is indeed a depleting resource. It is somewhat soft (6-7 on Moh's scale of hardness), and has a direction of cleavage, along which it can be easily broken. It is desirable because of its' elegant and opulent color.
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All purple and blue varieties of the stone are the result of heat treatment. The stone is a yellowish-brown "bug juice" color when it is mined, but when heated to between 800-900 degrees Fahrenheit, it becomes that gorgeous violet blue that is used in jewelry. The stone has never been found in another locality, so it is indeed a depleting resource. It is somewhat soft (6-7 on Mohs scale of hardness) and has a direction of cleavage along which it can be easily broken. It is desirable because of its elegant, opulent color.

Revision as of 20:59, 23 December 2006

Tanzanite
Chemical composition Calcium aluminum silicate
Crystal system Orthorhombic
Habit Prismatic
Cleavage Perfect, prismatic
Fracture Uneven
Hardness 6.5
Optic nature Biaxial +
Refractive index 1.685-1.707
Birefringence 0.008
Dispersion Low, 0.012
Specific gravity 3.35
Lustre Vitreous
Pleochroism Strong trichroism (dichroism in heated)

Tanzanite, a variety of zoisite, was discovered in the Merelani district of Tanzania near Mount Kilimanjaro in 1967. So far, all tanzanite discovery has been limited to a six kilometer strip in this area, which was divided into four blocks, labeled A, B, C and D. Block C is the only site still commercially producing rough tanzanite at this time.

All purple and blue varieties of the stone are the result of heat treatment. The stone is a yellowish-brown "bug juice" color when it is mined, but when heated to between 800-900 degrees Fahrenheit, it becomes that gorgeous violet blue that is used in jewelry. The stone has never been found in another locality, so it is indeed a depleting resource. It is somewhat soft (6-7 on Mohs scale of hardness) and has a direction of cleavage along which it can be easily broken. It is desirable because of its elegant, opulent color.