COMPARE GUIDE
Red SpinelVSSynthetic Red Spinel
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
- ◎ is higher in Synthetic Red Spinel, 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: Red Spinel | B: Synthetic Red Spinel | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.712–1.736 | 1.727–1.735 | Overlap |
| Specific gravity (SG) | 3.58–3.61 | 3.62–3.66 | B higher |
| Mohs hardness | 8.0 | 8.0 | Nearly equal |
| Birefringence | — | — | — |
| Dispersion | — | — | — |
| Property | A: Red Spinel | B: Synthetic Red Spinel |
|---|---|---|
| Crystal system | 等軸晶系 | 等軸晶系 |
| Pleochroism | — | — |
| Chelsea filter | red | red |
| UV (long-wave) | medium (red) | strong (red) |
| UV (short-wave) | weak (red) | medium (red) |
◆Natural red spinel (Mogok, Mahenge, Luc Yen) shows octahedral nclusions, natural color zoning, and characteristic chromium-iron absorption spectra. Synthetic red spinel shows and round gas bubbles diagnostic of Verneuil at 10× immersion. Strong UV is common to both but typically more intense in synthetic material.
Distinguishing tools
Tools that decide between Red Spinel and Synthetic Red 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.