1.7" Polished Zebra Stone (Ediacaran Microbialite?) - Australia

Zebra stone, or zebra rock, is a very unique reddish-brown and white-banded sedimentary rock from the Kimberley region in Western Australia. Composed essentially of small particles of quartz and ‘sericite’ (fine-grained white mica), zebra stone also contains the minerals kaolinite, dickite, and alunite. It was formed during the late Precambrian, around 670 million years ago. Several explanations for its formation have been proposed: one explanation states that the patterns were formed by the rhythmic precipitation of iron oxide-rich bands during the alteration of the rock by percolating fluids. Another explanation states that the patterns are caused by cyanobacterial mats infilling ripple marks in low energy shallow marine environments, which would make it a microbialite trace fossil.