"Zebrastone" SphereA Mineralogical Mystery
Johnny Cake Shale Formation, East Kimberly, Western Australia, Australia
Found only in the Johnny Cake Shale formation of Western Australia, this reddish-brown and white banded clay based rock is known as "Zebrastone". While the reddish-brown color can be attributed to the presence of iron oxides, the origin of its unique pattern of stripes and dots has yet to be explained by geologists. The present large sphere displays the distinctive pattern for which this mineral is known, culminating in a "bull's-eye" to one end, revealed by expert polishing which has produced a porcellaneous finish. Weight 19 lbs. Diameter 7½ in.