Unlike diamonds where cut grading dominates, colored gemstone valuation is 80% dictated by color purity—specifically Hue, Tone, and Saturation.

1. The "Big Three" Gemstone Quality Criteria

• Royal Blue Sapphires (Corundum): Prized for intense velvety royal blue saturation without dark extinction zones. Unheated Ceylon (Sri Lanka) and Madagascar stones command highest market premiums.
• Pigeon's Blood Rubies: The pinnacle of ruby valuation. Exhibits vivid, fluorescent red hue with medium tone. Burmese (Mogok) untreated stones represent top auction investments.
• Colombian Emeralds (Beryl): Known for pure radiant green hue. Natural microscopic inclusions ("jardin") are accepted as proof of natural origin; minor cedarwood oiling is industry standard.