The Cat's-Eye of Ketu

Cat's-eye chrysoberyl is the sharply chatoyant variety of chrysoberyl, beryllium aluminium oxide, in which dense parallel inclusions scatter light into a single bright line that crosses the dome of a cabochon and appears to open and close as the stone is turned. The best specimens show a milk-and-honey effect, one half of the stone milky and one half golden either side of the eye. Its principal traditional role is in jyotisha, Indian astrology, where it is the gem of Ketu, the descending lunar node, and one of the nine stones of the navaratna set worn together for planetary benefit. That astrological use is a real and continuous tradition with its own prescriptive literature. The wider claims made for the stone in modern crystal books, protection, sudden fortune, warding of the evil eye, overlap with the jyotisha reputation of Ketu but are stated in the general vocabulary of twentieth-century metaphysical publishing.