COMPARE GUIDE
PhenakiteVSRock Crystal / Quartz
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
- ◎ is higher in Phenakite, giving a numerical distinguishing point.
- ◎ is higher in Phenakite, giving a numerical distinguishing point.
- ◎ is higher in Phenakite, giving a numerical distinguishing point.
- ◎ is higher in Phenakite, 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: Phenakite | B: Rock Crystal / Quartz | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.654–1.670 | 1.544–1.553 | A higher |
| Specific gravity (SG) | 2.95–3.00 | 2.64–2.66 | A higher |
| Mohs hardness | 7.5–8.0 | 7.0 | A higher |
| Birefringence | 0.016 | 0.009 | A higher |
| Dispersion | — | — | — |
| Property | A: Phenakite | B: Rock Crystal / Quartz |
|---|---|---|
| Crystal system | 三方晶系 | 三方晶系 |
| Pleochroism | — | — |
| Chelsea filter | — | inert |
| UV (long-wave) | — | inert |
| UV (short-wave) | inert | inert |
◆Rock crystal (quartz) has RI 1.54–1.55, SG 2.65, and Mohs 7; phenakite has RI 1.65–1.67, SG 2.96, and Mohs 7.5–8 — the refractometer and the hydrostatic balance both give immediate separations.
Distinguishing tools
Tools that decide between Phenakite and Rock Crystal / Quartz 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.