This shard was part of a larger mosaic installed on the wall or ceiling of a building. Its structure allows us to examine the anatomy of a mosaic, in which many small tesserae were placed into plaster. Flecks of gold imply that these pieces would have flickered with the changing light.

Although tesserae are often created from small pieces of colored stone, this piece demonstrates that this was not always the case. Stones of any kind were incredibly expensive and, at times, completely unavailable for purchase. The tiny bubbles in these tesserae reveal that they are in fact glass, which were colored and broken down into tesserae to mimic stone.

—Ethan Bisselberg

Catalogue Record, Penn Museum