Star rubies are amongst the rarest and most coveted gems in the world
Star rubies are amongst the rarest and most coveted gems in the world. Even more so in comparison to star sapphires, since the chromium that colors them pink and red limits the sizes they can grow to. Each star ruby is so unique in appearance, that matching pairs (much less a set) is nearly impossible.
Special features that appear in gems like a star are known as phenomena . These effects include asterism , chatoyancy , iridescence, adularescence , aventurescence , labradorescence , and play-of-color . Rubies mainly show asterism, and rarely chatoyancy. It is possible for them to show other phenomena, but this happens only rarely.