Minerals and Metals in Ancient India v2.c43.s3.t3.2

v2.c43.s3.t3.2

Milky white or greenish white cloudy chrysoberyl samples (not the clear and transparent ones) exhibt chatoyancy. Extending across the curved surface of such stones is a silvery line or streak of light, when viewed in a strong light. These samples are called chrysoberyl or oriental cat’s eye. The phenomenon of chatoyancy is due to the existence in immense numbers of microscopically small cavities arranged in a particular direction or a bundle of microscopic channels running parallel to a single direction. When viewed at right angles to this direction, a band of light is visible running across this bundle. The stone is usually cut along this direction so that maximum number of light-reflecting cavities are close to or on the surface producing maximum chatoyancy.