Benitoite 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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Benitoite Gemstones by Size
This table shows distribution of Benitoite 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:0.33 cts
Heaviest:2.63 cts
Average:0.99 cts
Total photos:19
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| General Information | ||||||||||
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| Chemical Formula |
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| Benitoite Treatments | ||||||||||
| The deep blue color observed in some benitoite may have the same iron-titanium charge-transfer origin as does the blue in sapphire. It is doubtful that any of the corundum heat treatments could be applied successfully, however, since benitoite has a much lower melting point, being a silicate of composition BaTiSi3O9. G. Rossman has found (unpublished data) that benitoite gradually loses its blue color on heating in air at 600°C for 19 h. Irradiation with cobalt 60 returned some of the color center that is unrelated to the natural color – Nassau (1984) Heat-treatment may produce pinkish orange colors - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p. 3 | ||||||||||
| Physical Properties of Benitoite | ||||||||||
| Mohs Hardness | 6 to 6.5, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Specific Gravity | 3.61 to 3.68, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Cleavage Quality | None, Gemstones (2009) | |||||||||
| Fracture | Conchoidal, Gemstones (2009) | |||||||||
| Refractive Index | 1.757 to 1.804, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Optical Character | Uniaxial/+, Blue Chart Gem Identification (2010) More from other references | |||||||||
| Birefringence | 0.047, Blue Chart Gem Identification (2010) DoublingMore from other references | |||||||||
| Pleochroism | Strong dichroism: blue - colorless, Blue Chart Gem Identification (2010) More from other references | |||||||||
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