16.4.11: True Blue
- Page ID
- 4041
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| True Blue beryl | |
|---|---|
| Chemical composition | Be3Al2(SiO3)6Beryllium aluminum silicate |
| Crystal system | Hexagonal |
| Habit | Prismatic |
| Cleavage | Poor, basal |
| Fracture | Conchoidal to uneven |
| Hardness | 7.5 |
| Optic nature | Uniaxial - |
| Refractive index | 1.57 - 1.59 |
| Birefringence | 0.004 - 0,009 |
| Dispersion | Low, 0.014 |
| Specific gravity | 2.69 |
| Lustre | Vitreous |
| Pleochroism | Distinct (shades of body color) |
Discovered in the Yukon, Canada in 2004. An exceptionally dark blue aquamarine, whose color is the result of an extremely high concentration of iron. Unlike the Maxixe beryl, the color is photostable, which means that it is resistant to fading.
True Blue Beryl is a trade name for medium to dark blue aquamarine from Canada, marketed by True North Gems.
External links
- True North Gems
- Mineralogical and geochemical study of True Blue Aquamarine .. (pdf format)