Alexandrite for sale at wholesale prices. Alexandrite is the color change variety of the mineral Chrysoberyl. In order to be classified as a true Alexandrite, it must how a distinct color change from red to green. The change in color is due to the way the stone absorbs certain wavelengths of light. In incandescent lighting yellow lights common used in households) there is no blue / green component of light so the stone looks red or pink. In blue light (like fluorescent light) there is component of blue and green light so the stone will look greener.