Roman glass cameos[edit]
During the Roman period the cameo technique was used on glass blanks, in imitation of objects being produced in agate or sardonyx. Cameo glass objects were produced in two periods; between around 25 BC and 50/60 AD, and in the later Empire around the mid-third and mid-fourth century.[4] Roman glass cameos are rare objects, with only around two hundred fragments and sixteen complete pieces known,[4] only one of which dates from the later period.[5] During the early period they usually consisted of a blue glass base with a white overlying layer,[6] but those made during the later period usually have a colourless background covered with a translucent coloured layer.[5] Blanks could be produced by fusing two separately cast sheets of glass, or by dipping the base glass into a crucible of molten overlay glass during blowing.[6] The most famous example of a cameo from the early period is the Portland Vase.