What is "zultanite"

n. A gemstone that shifts from varying shades of green in sunlight to a pinkish brown in incadescent light.

Zultanite is a trademark for a gem variety of the mineral diaspore, mined in the İlbir Mountains of southwest Turkey at an elevation of over 4,000 feet. Depending on its light source, zultanite’s color varies between a yellowish green, light gold, and purplish pink.