Amongst the Roman elite, tablewares were often fashioned from the precious hardstone sardonyx. Less expensive imitations were created using a mixture of white and amber glass. These so-called "onyx" wares were created using a "jelly roll" pattern. Sheets of amber and white glass were rolled together to form a cylindrical rod. The rod was sliced into discs and a few of these were fused together. As the glass was molded, each disc's pattern became distorted so that it took on the appearance of real sardonyx.
Glass also was used to simulate other popular hardstones such as agate, with its banded greyish blue and white structure; and fluorspar, with its diffuse bands of blue and purple that run through an otherwise near-colorless structure.
These and all mosaic wares only stayed in fashion until the time of Nero (reigned, A.D. 54-68), when the pendulum of Roman taste swung towards decolorized waresçcompletely transparent vessels which mimicked precious rock-crystal.