Gahnospinel Value, Price, and Jewelry Information


blue spinel
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

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

See the entire Gem Price Guide.

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Gahnospinel Information

DataValue
NameGahnospinel
Is a Variety ofSpinel
Crystallography Isometric
Refractive Index 1.716 - 1.780
Colors Green or blue, usually dark in tone
Polish Luster Vitreous
Fracture Luster Vitreous
Fracture Conchoidal
Hardness 7.5 - 8
Toughness Good
Specific Gravity 3.58 - 4.41
Birefringence None
Cleavage Indistinct
Dispersion 0.020
Enhancements None known
Transparency Transparent to translucent
UV LongInert
UV ShortInert
Absorption Spectrum Bands at 570 and 700, 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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