Our Gems vs Natural Gems
| Ramaura™ Cultured Ruby | Natural Ruby | Nicholas Created Alexandrite | Natural Alexandrite | Empress Cultured Emerald | Natural Emerald |
| Hardness | 9.0 | 9.0 | 8.5 | 8.5 | 8 | 7.5 - 8 |
| Specific Gravity | 3.96 - 4.00 | 3.96 - 4.00 | 3.75 | 3.70 - 3.72 | 2.65 - 2.67 | 2.67 - 2.78 |
| Mineral | Corundum | Corundum | Chrysoberyl | Chrysoberyl | Beryl | Beryl |
| Crystal System | Hexagonal | Hexagonal | Orthorhombic | Orthorhombic | Hexagonal | Hexagonal |
| Composition | Al2O3+Cr+3 | Al2O3+Cr+3 | BeAl2O4+Cr+3 | BeAl2O4+Cr+3 | Be3Al2Si6O18+Cr+3 | Be3Al2Si6O18+Cr+3 |
| Refractive Index | 1.760 - 1.770 | 1.760 - 1.770 | 1.746 - 1.756 | 1.744 - 1.755 | 1.561 - 1.565 | 1.565 - 1.582 |
| Birefringence | 0.008 | 0.008 | 0.010 | 0.011 | 0.003 - 0.005 | 0.005 - 0.009 |