chrysoberyl
chrysoberyl
An orthorhombic mineral, BeAl2O4; vitreous; green, brown, yellow, or red (alexandrite variety appears emerald green in sunlight, but red by incandescent light); occurs in granites, granite pegmatites, schists, and alluvial deposits; a gemstone. Gem varieties: alexandrite, chrysopal, cymophane, and golden beryl. Known as cat's-eye when it has chatoyancy. chrysopal.