tessera

noun3

1. •
   A small square piece of stone, wood, ivory or glass used for making a mosaic.

   • The map was laid using tesserae, small cube-shaped tiles of limestone, marble, or colored stone. — 2014
2. •
   A complex-ridged surface feature seen on plateau highlands of Venus and perhaps on Triton.
3. •
   (rare) An ancient Roman die.

   • During the reign of Augustus, Rome imported marble from Egypt and Africa, and games of tali and tessera were played. — 1971