What is the difference between chrysoberyl and alexandrite?
Chrysoberyl is the species name and Alexandrite is the variety name. Alexandrite is that variety of chrysoberyl that changes color as a function of the light source; green in daylight and red under incandescent light. Chrysoberyl is normally yellow, yellow-green, or brownish with its color being caused by the presence of iron. Spectroscopic analysis will reveal a strong band where the violet takes over from the blue. As the color darkens from bright yellowish-green to golden-yellow to brown, this band increases in strength. When the stone has a strong color, two additional bands can be seen in the green-blue. The most common inclusions are liquid-filled cavities containing three-phase inclusions. Stepped twin planes may be apparent in some cases. Some very rare mint bluish-green chrysoberyls from Tanzania owe their color to the presence of vanadium. These stones are quite rare and exceptional specimens can command prices as high as alexandrite. Alexandrite results from the small scale
