COMPARE GUIDE
Synthetic AmethystVSSynthetic Purple Sapphire
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
- ◎ is higher in Synthetic Purple Sapphire, giving a numerical distinguishing point.
- ◎ is higher in Synthetic Purple Sapphire, giving a numerical distinguishing point.
- ◎ is higher in Synthetic Purple Sapphire, giving a numerical distinguishing point.
- ◎ is higher in Synthetic Amethyst, giving a numerical distinguishing point.
Note: properties whose numeric ranges do not overlap are auto-extracted. Both are measurable with a refractometer or heavy-liquid bath.
| Property | A: Synthetic Amethyst | B: Synthetic Purple Sapphire | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.544–1.553 | 1.762–1.770 | B higher |
| Specific gravity (SG) | 2.64–2.66 | 3.98–4.05 | B higher |
| Mohs hardness | 7.0 | 9.0 | B higher |
| Birefringence | 0.009 | 0.008 | A higher |
| Dispersion | — | — | — |
| Property | A: Synthetic Amethyst | B: Synthetic Purple Sapphire |
|---|---|---|
| Crystal system | 三方晶系 | 六方晶系（三方晶系） |
| Pleochroism | 弱（紫・赤紫） | 中〜強（紫・赤紫） |
| Chelsea filter | inert | — |
| UV (long-wave) | inert | — |
| UV (short-wave) | inert | medium (red) |
◆Synthetic amethyst is SiO₂ : Fe (quartz, trigonal) with RI 1.544–1.553, SG 2.65, Mohs 7, and generally inert UV. Synthetic purple sapphire is Al₂O₃ : Cr, Ti (corundum, trigonal) with RI 1.760–1.770, SG 3.95–4.03, Mohs 9, and weak-to-moderate red UV. Mohs and refractometer immediately settle the species question.
Distinguishing tools
Tools that decide between Synthetic Amethyst and Synthetic Purple Sapphire 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.