COMPARE GUIDE
Almandine GarnetVSNatural Ruby
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
Decisive distinctionsDECISIVE
- ◎ is higher in Natural Ruby, 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.
Physical propertiesPROPERTIES
| Property | A: Almandine Garnet | B: Natural Ruby | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.770–1.830 | 1.762–1.770 | Overlap |
| Specific gravity (SG) | 3.95–4.30 | 3.97–4.05 | Overlap |
| Mohs hardness | 7.0–7.5 | 9.0 | B higher |
| Birefringence | — | 0.008 | — |
| Dispersion | — | — | — |
Optics & fluorescenceOPTICS & UV
| Property | A: Almandine Garnet | B: Natural Ruby |
|---|---|---|
| Crystal system | 等軸晶系 | 六方晶系（三方晶系） |
| Pleochroism | — | 強（紫赤・黄赤） |
| Chelsea filter | inert | red |
| UV (long-wave) | inert | strong (red) |
| UV (short-wave) | inert | weak (red) |
ObservationOBSERVATION
◆Ruby fluoresces strongly red under LW UV; almandine is inert. Ruby is doubly refractive; almandine is singly refractive.
Color categoriesCATEGORIES
A: Almandine Garnet
Red / pink
B: Natural Ruby
Red / pink
DISTINGUISHING TOOLS · 3 ITEMS
Distinguishing tools
Tools that decide between Almandine Garnet and Natural Ruby 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.