An engraved gem is a small gemstone, usually semi-precious, that has been carved, in the Western tradition normally with images or inscriptions only on one face. The engraving of gemstones was a major luxury art form in the ancient world, and an important one in some later periods.Strictly speaking, engraving means carving in intaglio, with the design cut into the flat background of the stone, but relief carvings, with the design projecting out of the background as in nearly all cameos, are also covered by the term (this article uses ""cameo"" in its strict sense, to denote a carving exploiting layers of differently coloured stone). The activity is also called gem carving, and the artists gem-cutters. References to antique gems, and intaglios in a jewellery context, will almost always mean carved gems. Vessels like the Cup of the Ptolemies and heads or figures carved in the round are also known as ""hardstone carvings"" and similar terms.Glyptics, or ""glyptic art"", covers the field of small carved stones, including cylinder seals and inscriptions, especially in an archaeological context. Though they were keenly collected in antiquity, most carved gems originally functioned as seals, often mounted in a ring; intaglio designs register most clearly when viewed by the recipient of a letter as an impression in hardened wax. A finely carved seal was practical, as it made forgery more difficult - the distinctive personal signature did not really exist in antiquity.