Tesserae

Tesserae are small pieces used in the creation of a mosaic surface. The term tesserae is Latin for a small cube or tile; the singular form is tessera and the plural tesserae. These pieces are typically made from glass, ceramic, or natural stone, but other materials such as smalt (colored glass) and metal may also be used. In the Byzantine world, gold tesserae—thin sheets of gold backed by glass—were employed to produce luminous areas in religious interiors. Tesserae vary in size, from a few millimeters to several centimeters, depending on tradition and the desired level of detail. They are usually cut to fit the intended design and set into a bed of mortar or plaster, with grout filling the gaps.

Application and technique involve arranging tesserae to control color, shading, and texture. The standard approach is opus tessellatum, where regular tesserae form wide areas of color and light effects, while more detailed work may use smaller pieces and specialized layouts such as vermiculations around figures to achieve finer contours.

History and usage span ancient to modern periods. Mosaic tesserae date to ancient Greece and Rome and became central in Byzantine art, where elaborate interiors relied on glass and gold tesserae to create radiant surfaces. In contemporary practice, tesserae are commercially produced in a range of colors and materials and are used in architectural floors and walls, as well as standalone mosaic artworks throughout the world.