Sapphire & Ruby (Corundum) Faceting Diagrams

Recommended Rough: Blue sapphire, Padparadscha, ruby, Montana sapphire, lab-grown corundum

Corundum (sapphire and ruby, RI 1.76, critical angle 34.6°) is the benchmark colored gemstone for custom faceting: Mohs 9 durability paired with enough refractive power to support bold contrast patterns without pavilion leakage.

Every RI 1.76 pattern below is numerically optimized for corundum's 34.6° critical angle across real tilt angles, balancing bright light return against crisp head-shadow contrast so dark tones stay lively instead of extinguishing and pale rough avoids center windowing.