When observing gemstones with birefringences, one may occasionally observe differences in shading or color changes. This is referred to as pleochroism (“many color), and is caused by absorption light at different wavelengths by gemstones. A gemstone with two colors is said to have dichroism; 3 colors is referred to as trichroism. Care should be taken during cutting and refining of pleochroic gemstones to select the best direction of the crystal arrangement in order to emphasize the colors of these gemstones.