closed as off-topic by user12525, Peter Jansson, arkaia, Ash, Jan Doggen Jul 11 at 7:09
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "Please review our rock identification guidelines to provide the missing information so that your question is both answerable and useful to new users." – Community, Peter Jansson, arkaia, Ash, Jan Doggen
Your rock appears to be a sandstone cobble displaying iron oxide banding. The banding is the result of redox reactions of iron and oxygen from water passed through the rock. A oversimplified view would be that the iron oxide staining advanced inward from the outer edge of the rock until the water source was removed. The result is the pattern left in the rock. Similar to salt staining that forms on baseball caps caused by sweat that seeps into the hat and then evaporates.