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Brown ZirconVSSmoky Quartz
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
- ◎ is higher in Brown Zircon, giving a numerical distinguishing point.
- ◎ is higher in Brown Zircon, giving a numerical distinguishing point.
- ◎ is higher in Brown Zircon, 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: Brown Zircon | B: Smoky Quartz | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.810–1.984 | 1.544–1.553 | A higher |
| Specific gravity (SG) | 4.00–4.70 | 2.64–2.66 | A higher |
| Mohs hardness | 7.0–7.5 | 7.0 | Overlap |
| Birefringence | 0.020 | 0.009 | A higher |
| Dispersion | 0.039 | — | — |
| Property | A: Brown Zircon | B: Smoky Quartz |
|---|---|---|
| Crystal system | 正方晶系 | 三方晶系 |
| Pleochroism | — | 弱〜中（茶・赤茶） |
| Chelsea filter | — | inert |
| UV (long-wave) | — | inert |
| UV (short-wave) | weak (yellow) | inert |
◆Smoky quartz is SiO₂ (silicon dioxide) with Mohs 7, SG 2.65, RI 1.54–1.55, and weak (0.009) — no visible at 10× on cut stones. Brown zircon is ZrSiO₄ with Mohs 7–7.5, SG 4.0–4.7 (distinctively heavier in the hand), RI 1.81–1.984 (well above any quartz), and strong producing pronounced visible . The check alone — visible immediately under a 10× loupe — gives an unambiguous separation, and the specific gravity (zircon nearly twice as heavy) confirms it on first handling.
Distinguishing tools
Tools that decide between Brown Zircon and Smoky 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.