Alexandrite vs Amethyst
Alexandrite is harder (Mohs 8.5) than Amethyst (Mohs 7), so it resists scratching better.
Alexandrite has the higher refractive index (1.746–1.755 vs 1.544–1.553), which a refractometer can use to separate them.
Alexandrite is denser (SG 3.73 vs 2.65); a alexandrite of the same size weighs about 41% more.
Advertisement
Ad space (in-content)
| Property | Alexandrite | Amethyst |
|---|---|---|
| Species / material | Chrysoberyl | Quartz |
| Mohs hardness | 8.5 | 7 |
| Refractive index | 1.746–1.755 | 1.544–1.553 |
| Specific gravity | 3.73 | 2.65 |
| Crystal system | Orthorhombic | Trigonal |
| Birefringence | 0.008–0.010 | 0.009 |
Values are typical ranges from standard gemmological references; individual stones can vary.
Test it yourself
More comparisons
Diamond vs AlexandriteDiamond vs AmethystRuby vs AlexandriteRuby vs AmethystSapphire vs AlexandriteSapphire vs AmethystEmerald vs AlexandriteEmerald vs AmethystAquamarine vs AlexandriteAquamarine vs AmethystMorganite vs AlexandriteMorganite vs AmethystAlexandrite vs SpinelAlexandrite vs TopazAlexandrite vs TourmalineAlexandrite vs Garnet (almandine)