eBay link, look like iron on inlays or something. The edges look like real clay to me....
https://www.ebay.com/itm/165060008552?hash=item266e57da68:g:By8AAOSwutVfqVBC
https://www.ebay.com/itm/165060008552?hash=item266e57da68:g:By8AAOSwutVfqVBC