The Encyclopedia · Stones & materials
Star sapphire
A sapphire cut as a cabochon to show a six-rayed star, caused by fine needles of rutile inside the stone.
The effect is called asterism. Star sapphires and star rubies were especially popular from the 1930s to the 1950s, often set in heavy gold rings and cufflinks. Synthetic star stones have been made since the late 1940s and are very common.
What to look for
A good natural star is sharp, centred and moves across the stone as it turns. A perfectly regular star on a flawless, evenly coloured stone is often synthetic; a laboratory can tell.
Related terms