Comparison Chart for Nocholas Created Alexandrite and Natural Alexandrite
| Nicholas Created Alexandrite | Natural Alexandrite | |
| Hardness | 8.5 | 8.5 |
| Specific Gravity | 3.75 | 3.70 - 3.72 |
| Mineral | Chrysoberyl | Chrysoberyl |
| Crystal System | Orthorhombic | Orthorhombic |
| Composition | BeAl2O4+Cr+3 | BeAl2O4+Cr+3 |
| Refractive Index | 1.746 - 1.756 | 1.744 - 1.755 |
| Birefringence | 0.010 | 0.011 |