From as early as 4000 BCE precious and semi-precious stones (gems) were cut, polished, and used for personal adornment. The earliest examples are found in Mesopotamia and Egypt, but cut gems were also popular in Cycladic, Cypriot, Minoan, and Mycenaean cultures. This art form was adopted by the Greeks in the 8th century BCE and continued through the Roman period. Many gemstones were believed to have magical powers and were worn as talismans, but the addition of images (and, later, inscriptions) enhanced their appearance, meaning and value.
Both translucent and opaque gemstones were used in the classical world, and color, rather than translucency, seems to have been more important. The jewelry settings for most gemstones were backed with gold, making them impenetrable to light. Frequently used gems include: carnelian (pale yellow to bright red), garnet and bloodstone (deep red), lapis lazuli (dark blue), amethyst (purple), chalcedony (white and light blue), and jasper, serpentine, and emerald (green).
The hardness of gemstones made them difficult to cut. Metal tools were used in combination with abrasive materials, such as sand, metal dust and stone chips. Bow drills and cutting wheels were also used. Engraved gems were incised (or engraved) with images in sunken relief; cameos had the background cut away, leaving a raised relief image. Cameos were usually made from striated stones, such as agate or sardonyx, in order to exploit the contrast provided by the different colored layers.