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Gray MoonstoneVSLabradorite
Side-by-side comparison of physical properties, fluorescence, and crystal system — to identify by observation.
- ◎ is higher in Labradorite, giving a numerical distinguishing point.
- ◎ is higher in Labradorite, giving a numerical distinguishing point.
- ◎ is higher in Labradorite, 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: Gray Moonstone | B: Labradorite | Verdict |
|---|---|---|---|
| Refractive index (RI) | 1.518–1.526 | 1.559–1.573 | B higher |
| Specific gravity (SG) | 2.55–2.61 | 2.65–2.75 | B higher |
| Mohs hardness | 6.0–6.5 | 6.0–6.5 | Nearly equal |
| Birefringence | 0.005 | 0.008 | B higher |
| Dispersion | — | — | — |
| Property | A: Gray Moonstone | B: Labradorite |
|---|---|---|
| Crystal system | 単斜晶系 | 三斜晶系 |
| Pleochroism | — | — |
| Chelsea filter | — | — |
| UV (long-wave) | — | — |
| UV (short-wave) | weak (orange) | inert |
◆Labradorite (Ca-Na plagioclase, anorthite-rich end of the series, RI 1.560–1.572, SG 2.68–2.72) shows — discrete, vivid colored flashes (blue, gold, green, violet) produced by light interference in coarser lamellar structure. Moonstone shows adularescence — a soft, billowy bluish-white sheen produced by lighter scattering through finer lamellae. The two phenomena are visually distinct: labradorite flashes are sharp-edged and shift across a few specific colors; moonstone is diffuse and consistently bluish-white. SG also separates them definitively (moonstone 2.56–2.59 vs labradorite 2.68–2.72).
Distinguishing tools
Tools that decide between Gray Moonstone and Labradorite 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.