The cornflower blue sapphire is the most prized variety of blue corundum, famous for its intense blue color reminiscent of cornflower blossoms, with a distinctive velvety appearance. This exceptional hue is considered the absolute reference of quality for blue sapphires.
9硬度（满分10）
Corundum所属矿物族
Heat TreatmentHigh-temperature heat treatment (1600-1800°C) is used to improve the color and clarity of sapphires. This treatment is permanent, stable, and widely accepted in the industry. Approximately 95% of blue sapphires on the market are heated. Treatment must be disclosed but does not significantly affect the stone's durability.
Untreated (Unheated)Untreated cornflower blue sapphires are extremely rare and represent less than 5% of the market. They command substantial premium prices, sometimes 3 to 10 times higher than heated stones of comparable quality. A prestigious laboratory certificate (GIA, GRS, SSEF, Gübelin) confirming no treatment is essential. Kashmir sapphires are particularly valued when untreated.
Beryllium DiffusionLess common treatment that introduces beryllium into the crystal structure to modify or intensify color. This method is controversial and must be clearly disclosed as it significantly affects value (70-90% reduction). Detectable only through laboratory analysis. Rarely used on cornflower blue quality sapphires.
