Gahnospinel Value, Price, and Jewelry Information

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Spinel - Locality: Hunza Valley, Gilgit District, Northern Areas, Pakistan. Size: 2.6 x 2.2 x 1.9 cm. A striking, 1.6 cm, lustrous, compound, octahedral, indigo-blue spinel crystal set atop contrasting snow-white marble from the Hunza Valley of Pakistan. Pristine, complete all-around and eminently viewable from both sides. By Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons

Gahnospinel Value

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Blue - Fine Color Blue: B 5/5

.5 to 2 carats
Faceted
to /ct
2 to 4 carats
Faceted
to /ct
4 carats plus
Faceted
to /ct

Red - Fine Color Red: R, slpR 5/5

.2 to 1 carat
Faceted
to /ct
1 to 5 carats
Faceted
to /ct

Pink

.5 to 1 carats
Faceted
to /ct
1 to 3 carats
Faceted
to /ct
3 carats plus
Faceted
to

Purple - Fine Color Purple: P 5/5: P, rP, bP, V 5/4

.5 to 1 carats
Faceted
to /ct
1 to 3 carats
Faceted
to /ct
3 carats plus
Faceted
to /ct

Other Colors - Fine Color Orange: O, rO 5/5

.5 to 1 carats
Faceted
to /ct
1 to 5 carats
Faceted
to /ct
5 carats plus
Faceted
to /ct

Star Spinel

All Sizes
Star Spinel
to /ct
View Gahnospinel Profile

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Highest values go to pure blue, size and clarity.

Gahnospinel Information

Data Value
Name Gahnospinel
Is a Variety of Spinel
Identifying Characteristics Dark tone
Formula (MgZn)Al2O4
Colors Green or blue, usually dark in tone
Fracture Conchoidal
Hardness 7.5-8
Cleavage Indistinct
Wearability Good
Crystallography Isometric.
Refractive Index 1.716-1.780
Birefringence None
Dispersion 0.020
Luminescence Inert.
Luminescence Present No
UV Long Inert
UV Short Inert
Absorption Spectrum Bands at 5700 and 7000, not always present.
Pleochroism None.
Luster Vitreous.
Polish Luster Vitreous.
Fracture Luster Vitreous.
Specific Gravity 3.58-4.41
Enhancements None known.
Transparency Transparent to translucent
Phenomena None.

Gahnospinels from Sri Lanka

Gahnospinels from Sri Lanka

ZnO(%)

FeO(%)

N

S.G.

0.14

2.34

1.716

3.6

7.18

1.92

1.723

3.72

10.27

2.52

1.731

3.77

12.98

1.47

1.737

3.86

18.21

1.93

1.747

3.97

24.81

1.90

1.752

4.05

 

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