Roman glassworkers sometimes finished their products by cutting, grinding, and polishing. They had learned these techniques from lapidaries, who employed them in completing works made of semiprecious stone. Very little is known about the tools used in this process, although the Roman writer Pliny provides some information about the working of semiprecious stones with abrasives. The same abrasives were probably also used in the cold-working of glass. Indeed, it is likely that some craftsmen worked with both materials. Some of the glass objects finished by cutting, engraving, and wheel abrading featured faceted decoration. One of them was a conical beaker with 11 rows of mostly diamond-shaped facets made by grinding and polishing. Similar beakers have been found all over the Roman Empire, in Scandinavia, and in Afghanistan.