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Natural White SapphireVSWhite Spinel
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
- ◎ is higher in Natural White Sapphire, giving a numerical distinguishing point.
- ◎ is higher in Natural White Sapphire, giving a numerical distinguishing point.
- ◎ is higher in Natural White Sapphire, 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: Natural White Sapphire | B: White Spinel | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.762–1.770 | 1.712–1.717 | A higher |
| Specific gravity (SG) | 3.95–4.03 | 3.58–3.61 | A higher |
| Mohs hardness | 9.0 | 8.0 | A higher |
| Birefringence | 0.008 | — | — |
| Dispersion | — | — | — |
| Property | A: Natural White Sapphire | B: White Spinel |
|---|---|---|
| Crystal system | 六方晶系（三方晶系） | 等軸晶系 |
| Pleochroism | — | — |
| Chelsea filter | inert | — |
| UV (long-wave) | inert | — |
| UV (short-wave) | weak (white) | strong (white) |
◆acet visible at 30× immersion through the table — spinel is singly refractive and never doubles. Refractometer immediately separates the two species (white sapphire's RI 1.762–1.770 is well above any spinel reading). White sapphire is also marginally harder (Mohs 9 vs spinel 8). The connoisseur trade increasingly favors natural colorless spinel over white sapphire for its softer optical character and its connection to the celebrated colored-spinel tradition.
Distinguishing tools
Tools that decide between Natural White Sapphire and White Spinel 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.