Stunning Queensland Boulder (Picture) Opal, These opals are truly unique. Sometimes during the cutting process of these opals from the Koroit opal fields, a picture appears. In this case an eagle's head has formed within the ironstone boulder rock. It is then very carefully cut and polished to keep and capture this image and to enhance its natural beauty. Very original and one of a kind pendant set in 925 sterling silver, size 2.5cmx2.5cm.