Circular Micromosaic Brooch Italian Micromosaic Round Brooch, possibly Roman. The glass mosaic pieces are mounted in an circular metal surround and depicts a floral posy against a green background encircled with sixteen small discs. Circa 1950. The brooch measures 1 1/2" in diameter. There are several types of Italian mosaics: Venetian, Roman and Florentine. In Venetian designs, the artisans used a wide variety of shapes in the glass tiles to form the design. In the Roman design very tiny pieces of colored glass, call tesserae, were pieced together to form a picture, and were held in place with cement in a glass or stone background. In the Florentine design pietra dura (literally, “hard stone”) were cut, shaped and fitted together, somewhat like a jigsaw puzzle to produce a picture. These normally used a bed of black marble as the foundation so they have a black background. Florentine designs normally used larger tiles.