Pastel blue sapphire is a variety of corundum prized for its soft and delicate color, ranging from tender sky blue to luminous pastel blue. This subtle hue offers a refined alternative to more intense blue sapphires.
9硬度（满分10）
Corundum所属矿物族
Heat TreatmentHeat treatment is applied to approximately 95% of sapphires. It permanently improves color and clarity. This treatment is widely accepted in the market and must be disclosed. Heated sapphires are worth 30-50% less than untreated ones of equivalent quality.
Untreated (Natural)Untreated pastel blue sapphires represent about 5% of the market and are highly sought after for their natural beauty. They command prices 1.5 to 3 times higher than heated stones. A laboratory certificate (GIA, GRS, SSEF, Gübelin) is essential to attest the absence of treatment.
Beryllium DiffusionTreatment that modifies color on the surface or in depth by beryllium diffusion. This treatment significantly affects value (reduction of 80-95%) and must be disclosed. Diffused stones sell at very low prices (3-50 EUR/ct).
