Glass mosaic fragment late 1st century B.C.-early 1st century A.D. Roman Thick base fragment, probably from a deep, footed ribbed bowl.Translucent deep purple, cobalt blue, and opaque white.Two layers fused together, forming a convex disk.Exterior layer: ribbon mosaic pattern formed from sections of a single cane in purple ground with white and blue threads in parallel lines; interior layer: spiraling mosaic pattern formed from sections of a single cane in blue ground with white threads.Polished convex exterior; pitting of surface bubbles and weathering in cracks; dulling, creamy weathering, and faint iridescence on exterior and jagged edges.Probably part of a deep ribbed bowl with base ring, but cut down, possibly in antiquity, into a disk.. Glass mosaic fragment. Roman. late 1st century B.C.-early 1st century A.D.. Glass; cast. Early Imperial. Glass