An exceptional and very rare Art Nouveau carving of an owl sitting on a tree branch, mounted in gold as a brooch. It's carved from boulder opal, which is a matrix of ironstone with opal veins. The vein of opal on the surface was carefully carved as front face of the owl, while the remaining ironstone was carved into a tree branch and the owl's back. Garnet details. Clasps with a safety catch, and an additional pin stem as a safety to thread through a lapel. Dates to c1900.