Notice the 2 ring-bezel marks at the top & bottom of the seal border, plus a disturbance in the body of the shard where a knuckle of the ring wearer probably collided with the wet clay during the stamping operation:

The actual dimensions of the 4 borders on this shard are 3.5" x 2.9" x 1.9" x 2.1" (88 x 73 x 49 x 53 mm); its thickness varies from 0.3" to 0.4" (7-11 mm); the seal is 0.8" x 0.6" (20 x 15 mm).