| Formula | Ca2Al3(SiO4)(Si2O7)O(OH) |
| Molecular mass | |
| admixture | |
| IMA Status | |
| Systematics according to IMA (Mills et al., 2009) | |
| Class | |
| Group | |
| Physical properties | |
| Color | Sapphire blue to amethyst purple |
| Dash color | White |
| Shine | Glass |
| Transparency | transparent |
| Mohs hardness | 6.5 – 7 |
| fragility | Fragile |
| Cleavage | Perfect |
| kink | uneven, brittle |
| Density | 3.35 g/cm³ |
| Crystallographic properties | |
| space group | |
| Syngony | Rhombic |
| Twinning | |
| Optical properties | |
| optical type | |
| Refractive index | 1.691 – 1.700 |
| Birefringence | 0.008-0.013 |
| dichroism | |
| optical relief | |
| Dispersion of optical axes | 0.021 |
| Pleochroism | Strong blue, crimson red, greenish yellow |
| Luminescence | Missing |
| Diffusion | |
Strode Anna
Anna Strod – director of the jewelry online store Myjewels.ru Author and editor of the jewelry blog Myjewels.ru
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