COMPARE GUIDE
Synthetic Alexandrite (Flux / Hydrothermal)VSNatural Alexandrite
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
| Property | A: Synthetic Alexandrite (Flux / Hydrothermal) | B: Natural Alexandrite | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.745–1.755 | 1.745–1.755 | Nearly equal |
| Specific gravity (SG) | 3.71–3.75 | 3.71–3.75 | Nearly equal |
| Mohs hardness | 8.5 | 8.5 | Nearly equal |
| Birefringence | 0.009 | 0.009 | Nearly equal |
| Dispersion | — | — | — |
| Property | A: Synthetic Alexandrite (Flux / Hydrothermal) | B: Natural Alexandrite |
|---|---|---|
| Crystal system | 斜方晶系 | 斜方晶系 |
| Pleochroism | 強（緑・赤紫・黄橙） | 強（緑・赤紫・黄橙） |
| Chelsea filter | red | red |
| UV (long-wave) | strong (red) | weak (red) |
| UV (short-wave) | medium (red) | weak (red) |
◆nclusions, and natural growth zoning absent in synthetic material. Flux-grown synthetics show angular flux residue and platinum-crucible flakes diagnostic at 30× immersion; hydrothermal synthetics show chevron growth patterns and seed-crystal residue. RI 1.745–1.755, SG 3.71–3.75, Mohs 8.5, and color-shift behavior are essentially identical between fine flux/hydrothermal synthetic and natural — only morphology and FTIR/UV-Vis spectra reliably separate them at lab grade.
Distinguishing tools
Tools that decide between Synthetic Alexandrite (Flux / Hydrothermal) and Natural Alexandrite in practice.
Note: this page is auto-generated from published GIA / CGL reference values. Individual stones, treatments, and synthetics may fall outside these ranges. For a definitive identification, consult an accredited gem laboratory.