A tessera (plural: tesserae) is an individual tile in a mosaic, usually formed in the shape of a cube.

In antiquity, mosaics were formed from naturally colored pebbles, but by 200 BCE purpose-made tesserae were being used. Marble or limestone was cut into small cubes that were arranged into the required design. Later, tesserae were made from colored glass, or clear glass backed with metal foils.

Tesserae is also the term for dice used in ancient Rome and for the layers of calcification on shark scales. Several commercial enterprises operate under the name Tessera or Tesserae, usually because their products deal in grids of some form.

See also

The Mosaic article describes techniques for assembling tesserae into a design on different surfaces.