Tanzanite is called after the East African state of Tanzania, it was discovered in the Mererani Hills of Northern Tanzania in 1967. Tanzanite is trichroic i.e when light enters it appear alternately sapphire blue, violet and burgundy. Tanzanite is usually a reddish brown in its rough state. Heating occurring underground naturally or in a furnace removes the brown or burgundy color. Tanzanite becomes dichroic when heated; its colour changes blue-purple to purple-blue. Some of the tanzanite is applied with a layer containing cobalt, to improve the color.
Tanzanite Treatments:-
When heated to 752 - 932 degrees F (400 - 500 degrees C), the interfering yellowish and brown tints vanish, and the blue becomes deeper. - Gemstones of the world, Walter Schumann, 2001, p 160
Significant Gem Localities:-
Tanzania
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Hardness 6.5
GEMSTONE WEIGHT PER PIECE OF NATURAL TANZANITE
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PEAR
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MARQUISE
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SIZE
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WEIGHT
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SIZE
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WEIGHT
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4 x 3MM
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0.170
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4x2
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0.070
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5 x 3MM
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0.220
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5x2.5
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0.130
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6 x 4MM
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0.360
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6x3
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0.220
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7 x 5MM
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0.700
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7x3.5
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0.400
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8 x 5MM
|
0.850
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8x4
|
0.580
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9 x 6MM
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1.400
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10x5
|
1.100
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10 x 7MM
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2.100
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12x6
|
1.400
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GEMSTONE WEIGHT PER PIECE OF NATURAL TANZANITE
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OVAL
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EMERALD
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SIZE
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WEIGHT
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SIZE
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WEIGHT
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5 x 3MM
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0.230
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6x4MM
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0.600
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5 x 4MM
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0.300
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7x5MM
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1.000
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6 x 4MM
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0.450
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8x6MM
|
1.800
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7 x 5MM
|
0.850
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9x7MM
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3.000
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8 x 6MM
|
1.200
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9 x 7MM
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2.000
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GEMSTONE WEIGHT PER PIECE OF NATURAL TANZANITE
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PRINCESS
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HEART
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SIZE
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WEIGHT
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SIZE
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WEIGHT
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3.00MM
|
0.150
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4.00MM
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0.220
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3.50MM
|
0.220
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4.50MM
|
0.320
|
4.00MM
|
0.300
|
5.00MM
|
0.450
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4.50MM
|
0.500
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5.50MM
|
0.600
|
5.00MM
|
0.650
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6.00MM
|
0.750
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5.50MM
|
0.800
|
6.50MM
|
0.850
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6.00MM
|
1.000
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7.00MM
|
1.100
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6.50MM
|
1.250
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7.50MM
|
1.300
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7.00MM
|
1.650
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8.00MM
|
1.600
|
7.50MM
|
1.900
|
8.50MM
|
|
8.00MM
|
2.350
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9.00MM
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|
GEMSTONE WEIGHT PER PIECE OF NATURAL TANZANITE
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ROUND
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TRILLION
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SIZE
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WEIGHT
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SIZE
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WEIGHT
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SIZE
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WEIGHT
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1.50MM
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0.025
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3.20MM
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0.130
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4.00MM
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0.220
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1.60MM
|
0.027
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3.30MM
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0.140
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4.50MM
|
0.320
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1.70MM
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0.028
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3.40MM
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0.150
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5.00MM
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0.450
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1.80MM
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0.030
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3.50MM
|
0.160
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5.50MM
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0.570
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1.90MM
|
0.035
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3.60MM
|
0.180
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6.00MM
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0.750
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2.00MM
|
0.040
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3.70MM
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0.200
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6.50MM
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0.900
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2.10MM
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0.044
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3.80MM
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0.220
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7.00MM
|
1.100
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2.20MM
|
0.048
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3.90MM
|
0.240
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7.50MM
|
1.400
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2.30MM
|
0.050
|
4.00MM
|
0.270
|
8.00MM
|
1.800
|
2.40MM
|
0.055
|
4.50MM
|
0.400
|
8.50MM
|
1.900
|
2.50MM
|
0.060
|
5.00MM
|
0.540
|
9.00MM
|
2.300
|
2.60MM
|
0.070
|
5.50MM
|
0.650
|
9.50MM
|
2.600
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2.70MM
|
0.080
|
6.00MM
|
0.750
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10.00MM
|
3.050
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2.80MM
|
0.090
|
6.50MM
|
0.900
|
10.50MM
|
3.400
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2.90MM
|
0.100
|
7.00MM
|
1.100
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11.00MM
|
3.950
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3.00MM
|
0.120
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7.50MM
|
1.300
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11.50MM
|
4.500
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3.10MM
|
0.125
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8.00MM
|
1.600
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12.00MM
|
5.000
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