This is a MacBeth-Evans Ivrene Petalware 10 3/4" salver plate or platter. It is translucent at the rim and solid ivory in the center. This color was originally called Ivrene, now some people call it beige, cream, ivory, or Cremax/Monax. Cremax and Monax are names used by MacBeth-Evans, but not for this specific color. Petalware was produced from 1930-1950, it is authentic Depression Glass.
MacBeth Evans Ivrene Ivory Petalware Plate Platter