COMPARE GUIDE
Blue TopazVSParaíba Tourmaline
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
Decisive distinctionsDECISIVE
- ◎ is higher in Blue Topaz, giving a numerical distinguishing point.
- ◎ is higher in Blue Topaz, giving a numerical distinguishing point.
- ◎ is higher in Paraíba Tourmaline, 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: Blue Topaz | B: Paraíba Tourmaline | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.610–1.620 | 1.620–1.640 | Overlap |
| Specific gravity (SG) | 3.50–3.57 | 3.06–3.10 | A higher |
| Mohs hardness | 8.0 | 7.0–7.5 | A higher |
| Birefringence | 0.010 | 0.018 | B higher |
| Dispersion | — | — | — |
Optics & fluorescenceOPTICS & UV
| Property | A: Blue Topaz | B: Paraíba Tourmaline |
|---|---|---|
| Crystal system | 斜方晶系 | 三方晶系 |
| Pleochroism | 中（青・無色） | 強（青緑・緑） |
| Chelsea filter | inert | inert |
| UV (long-wave) | inert | inert |
| UV (short-wave) | inert | inert |
ObservationOBSERVATION
◆Blue topaz is heavier (SG ~3.5), shows weaker , and lacks the electric saturation. Most blue topaz is irradiated colorless material.
Color categoriesCATEGORIES
A: Blue Topaz
Blue
B: Paraíba Tourmaline
Blue
DISTINGUISHING TOOLS · 3 ITEMS
Distinguishing tools
Tools that decide between Blue Topaz and Paraíba Tourmaline 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.