National Museum of Natural Science

Red corundum is called ruby. It is a well-known gemstone type of the corundum family. On display is a rough, uncut columnar-shaped ruby from Afghanistan with crystal length of approximately 2.5 centimeters. The color is bright and beautiful and this specimen is of gemstone quality. When illuminated under short ultraviolet waves, burgundy red fluorescence is produced. On rare occasions, long, thin needle-shaped bundles in symmetrical arrangement of three intersecting sets appear within the crystals. If processing and polishing are carried out along the vertical C-axis, the effect is one of hexagonal asterism when viewed under light. In this display is a stunning, vivid red, star ruby gemstone ring. 

Ruby