Vintage designer plate..rare

Rare Vintage Plate. This was my mother's pottery plate. She paid over $300 for in the 90's. My mother is deceased and cannot find receipt nor the name of the designer of this plate. It is very heavy. I am selling it for $200. It is an original. I would love to find the name of this designer for I cannot find any name or symbol on the plate. Weight 4.10 pounds. it looks like inlaid tiles. it is beautiful