The color-changing sapphire is an exceptionally rare variety of corundum that displays a color change depending on the light source, typically shifting from blue-green in natural light to violet-purple in incandescent light. This rare optical phenomenon is caused by the combined presence of chromium and vanadium in the crystal structure.
9硬度（满分10）
Untreated (Natural)Untreated color-changing sapphires are extremely rare and command the highest prices. They must be accompanied by a laboratory certificate confirming the absence of treatment. The natural rarity of these stones makes them highly sought-after collector's items.
Heat TreatmentHeat treatment can improve clarity and intensify colors, but it can also affect the color-change phenomenon. Heated sapphires must be disclosed and are valued less than natural stones.
Diffusion TreatmentRare treatment for color-changing sapphires. This treatment modifies surface color and must be disclosed as it significantly affects value. Generally not accepted for fine gemstones.
