Gahnite Gemstones by Colour
This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
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Gahnite Gemstones by Size
This table shows distribution of Gahnite gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:0.20 cts
Heaviest:1.17 cts
Average:0.62 cts
Total photos:5
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| General Information | ||||||||||
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| Chemical Formula |
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| Physical Properties of Gahnite | ||||||||||
| Mohs Hardness | 7.5 to 8, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Specific Gravity | 4.40 to 4.65, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Optical Properties of Gahnite | ||||||||||
| Refractive Index | 1.790 to 1.818, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Optical Character | Isotropic, Blue Chart Gem Identification (2010) Anomalous double refraction | |||||||||
| Colour | ||||||||||
| Colour (General) | Blue, blue-green, green, Gemmological Tables (2004) More from other references | |||||||||
| Causes of Colour | Blue, Fe2+ in tetrahedral coordination, Pragmatic Spectroscopy For Gemologists (2011) | |||||||||
| Transparency | Transparent, Gemmological Tables (2004) More from other references | |||||||||
| Crystallography of Gahnite | ||||||||||
| Crystal System | Isometric, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Habit | Octahedra, Gems, Sixth Edition (2006) | |||||||||
| Geological Environment | ||||||||||
| Where found: | Natural gahnite occurs as an accessory mineral in granites and granite pegmatites., Gems, Sixth Edition (2006) | |||||||||
| Further Information | ||||||||||
| Mineral information: | Gahnite information at mindat.org | |||||||||
| Significant Gem Localities | ||||||||||
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