Gahnospinel Value, Price, and Jewelry Information

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

Gahnospinel Value

Highest values go to pure blue, size and clarity.

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Spinel Value via Gem Price Guide

Fine Color Blue: B 5/5
Blue .5 to 2 carats 2 to 4 carats 4 carats plus
Faceted to /ct to /ct to /ct
Fine Color Red: R, slpR 5/5
Red .2 to 1 carat 1 to 5 carats
Faceted to /ct to ,000/ct
Pink .5 to 1 carats 1 to 3 carats 3 carats plus
Faceted to /ct to ,000/ct to
Fine Color Purple: P 5/5: P, rP, bP, V 5/4
Purple .5 to 1 carats 1 to 3 carats 3 carats plus
Faceted to /ct to ,800/ct to ,000/ct
Fine Color Orange: O, rO 5/5
Other Colors .5 to 1 carats 1 to 5 carats 5 carats plus
Faceted to /ct to /ct to ,000/ct
Star Spinel All sizes
to /ct

Gahnospinel Information

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

(MgZn)Al2O4

Pleochroism

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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