Color-change sapphires are a sight to behold. They possess an intrinsic, almost magical quality that captivates the eyes and spirit of the person gazing at them. They change color depending on the light environment. It is like having many colors in one. They are very rare, treasured, and very costly in large sizes. However, fine daylight colors with a good change in incandescent environments can be relatively affordable in a smaller size.

Traditionally, the two lighting sources that allow for clear appreciation of color change sapphires are daylight, with strong direct sun preferred, and incandescent-filament light or candlelight.

Incandescent light is nowadays obsolete, and you will find so many different kinds of other artificial lights, like fluorescent, LED lights that mimic daylight, and so on. You will find that your color-changing sapphire will vary in hue and color accordingly. Sapphires, in general, are chameleon gemstones.

The major varieties of color change sapphires are from Sri Lanka and Madagascar, which will change in fine specimens from a violetish blue to purple. The other major variety is sapphires from East Africa, specifically regions like Songea, Tunduru, & Umba, which change from a tealish green in daylight to a brownish, reddish-purple in incandescent light. 

Color-change sapphires are usually left untreated, not heated, and completely natural, to preserve the color change or hue shift of the stone.