Color change garnet vs Alexandrite on Apr 5 2009, at 00:40 in Are there any other gemstones which change color?
Without gemological testing, color change garnets and alexandrites can be very difficult to distinguish. Both alexandrite and color change garnet can exhibit an intense color change. The main difference is their responses to different light sources. While the colors of alexandrite are similar in daylight and fluorescent light color change garnets
are distinctly green or bluish under fluorescent light but more blue gray or even lavender in daylight.
Color change garnets are notable for their color change throughout the day as a function of their sensitivity to the different color temperatures of morning and late afternoon light. To appreciate the full range of color change in these stones, one needs to observe the stones under early morning light, fluorescent light, late afternoon sunlight, and incandescent light. The best color change garnets are from Bekily in Madagascar and the new deposit in Chavia, Kenya.