Named for the gemologist George F. Kunz, kunzite is a phosphorescent gemstone, meaning it will absorb and later release ultraviolet light as visible light in darkness.

Kunzite is extremely sensitive to light and ultrasonic sound, and prolonged exposure to either of these will fade its color. For this reason, kunzite has often been called the “evening stone”.

Brown or green-violet stones may be heat-treated to improve their colors. Occasionally, stones will also be irradiated to darken their color. This process is considered “fair” in terms of its stability, but it may also remove the stone’s pleochroism.