Opus vermiculatum

Opus vermiculatum is a method of laying mosaic tesserae to emphasise an outline around a subject.

[1] Usually opus vermiculatum is meant to put emphasis on the main design and foreground details of a work, using a smooth and flowing halo-effect.

The method spread throughout the Hellenistic world; for instance, the large corpus of surviving examples found on the island of Delos.

One remarkable work in particular portrays a crucial scene in the Battle of Issus, and was possibly copied from a 4th-century BC Greek painting or fresco.

By then, mosaics were becoming increasingly impressionistic, taking advantage of the crystalline reflection of the tesserae, which was better suited to opus tessellatum.