COMPARE GUIDE
Orange GlassVSSpessartite Garnet
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
- ◎ is higher in Spessartite Garnet, giving a numerical distinguishing point.
- ◎ is higher in Spessartite Garnet, 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: Orange Glass | B: Spessartite Garnet | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.480–1.700 | 1.795–1.815 | B higher |
| Specific gravity (SG) | 2.30–4.50 | 4.12–4.20 | Overlap |
| Mohs hardness | 5.0–6.0 | 7.0–7.5 | B higher |
| Birefringence | — | — | — |
| Dispersion | — | — | — |
| Property | A: Orange Glass | B: Spessartite Garnet |
|---|---|---|
| Crystal system | 非晶質 | 等軸晶系 |
| Pleochroism | — | — |
| Chelsea filter | — | inert |
| UV (long-wave) | — | inert |
| UV (short-wave) | weak (yellow) | inert |
◆Spessartine garnet (Mn₃Al₂(SiO₄)₃, the manganese-aluminum garnet end member, Mohs 7–7.5, SG 4.12–4.20, RI 1.79–1.81, singly refractive cubic crystal, nclusions and growth-zoning under 10× immersion; glass shows regular round gas bubbles and pressing-die seams. The Namibian Kunene 'mandarin garnet' production (Werner Spaltenstein, 1991) and Tanzanian Loliondo deposits supply the high-grade natural material that orange glass most often imitates. Disclosure as 'glass' or 'imitation spessartine' is required under FTC Jewelry Guides §23.25.
Distinguishing tools
Tools that decide between Orange Glass and Spessartite Garnet 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.