Gem carving tecniques

Gem Carving: Materials and Techniques

Semi precious hard stones such as carnelian, chalcedony, amethyst, and agate have long been carved with decorative and figural designs. Intaglios As early as 5000 B.C., craftsmen in Mesopotamia used hand-powered tools to engrave images into stone blanks, creating intaglios (so called from the Italian intagliare, "to cut into"). Similar methods were employed by ancient artisans in Egypt, Greece, Rome, and Etruria. Intaglios were used to make relief impressions when pressed into wax, clay, or another sealing material. Cameos Around 250 B.C. a new carving technique developed: by cutting away the area surrounding a figure, artisans formed relief images known as cameos. The different hues of banded stones were exploited to enhance the appearance of depth with multicolored compositions.		. .

Cameos are created by carving into a top (often white)layer of stone to reveal the colored band underneath An intaglio (top) is cut below the surface of a gemstone, while a cameo (bottom) is carved in relief Carving Tools Although intaglios are concave and cameos are convex, both are produced in a similar fashion. A cutting tool dipped in a slurry of abrasive powder and oil is turned while a gemstone is manipulated against it. Cutters of different shapes and materials can be used—drills, wheels, cones, and balls made of copper, bronze, iron, or something softer such as wood or even reed. It is the powder (emery or corundum in antiquity, diamond dust today) carried by the tool, not the tool itself, that actually carves the stone. This engraving depicts an 18th-century carver along with a variety of cutting tools. The instruments used by ancient carvers were similar, being turned by a bow rather than a foot pedal. Image top right: Hermaphroditus Seated on an Altar (detail), possibly by Protarchos, 150–100 B.C. Sardonyx cameo set in a modern gold ring. The J. Paul Getty Museum, 2001.28.9