Sardonyx

Sardonyx is onyx in which bands of sard, red to brown, alternate with black or white ones; like all onyx it is a banded chalcedony, a form of quartz. Since ancient times its reds and yellows have often been produced or deepened by treatment. Minoan Crete used sardonyx in its art, notably in finds at Knossos, and is named in the Bible. Roman soldiers are said to have gone into battle wearing sardonyx amulets carved with Mars, god of war, believing they gave courage, and in Renaissance Europe wearing it was thought to make a speaker eloquent. Cunningham gives sardonyx projective energy, Mars, fire and the god Mars, with courage, protection, peace, eloquence, luck and happiness in marriage among its powers. He says it smooths things between lovers and married couples and helps them talk, is worn by lawyers and public speakers, and, kept near the heart, lifts low spirits towards peace and joy. Hall sees it as strengthening and protective, a stone that lends marriages steady, long-lived happiness, draws friends and good fortune, and can be set out around a house and garden to guard against crime.