Luminous tiger eye and sterling pendant

Tiger (or cat) eye stones have chatoyance, defined as: the property of some minerals to exhibit a wavy, luminous band with a silky lustre, reminiscent of the eye of a cat, in the centre of a cabochon-cut (polished, with a rounded, unfaceted convex surface) stone. The central band of this little pendant (15mm, 20mm with the bail) moves and expands as the piece turns. The colour also seems to change somewhat, with some purple spreading into the brown. The stone is nicely framed. Marked 925 on the back and in very good condition.