Chrysoberyl

The species name chrysoberyl is given to a transparent, faceted gemstone that does not show a color change between daylight and artificial light (the chrysoberyl which shows a color change is called alexandrite). The ideal colors of chrysoberyl are green and yellowish-green. In addition, due to strong dichroism, one may see an 
attractive bi-coloured chrysoberyl occasionally. Hardness is 8.5 on the Moh's scale. The high refractive index of the stone makes it very lively when properly cut and polished