Vintage Merck Sharp & Dohme mortar and pestle ashtray
The set is ceramic. It is white, although it is more of an off-white than a bright white.
The mortar has blue decoration on it that appears to be transferware. 
The mortar ashtray is 2" tall and 4-3/8" wide. The pestle is 3-3/4" long and 1-1/8" at the widest point.
Both pieces are in very good condition with no cracks, chips, or crazing. There is some staining on the unglazed bottom of the mortar.
Please see photos.