The technique of decorating the surface of a hard material (e.g. metal or a gemstone) from the front by incised lines, characters, patterns, portraits. etc., cut into the surface. When the decorationon a gemstone is so made, it is an intaglio.Engraving on gold was done from the third millennium BC, with crude tools of flint, bronze, copper and later iron; in Germany in the 15th century it was done with a dry-point needle.In modem times engraving is done by hand by means of a sharply pointed steel tool (called a burin 01 graver) while the metal is held on an engraver's block. Craftsmen skilled in calligraphy have doneengraving of monograms and inscriptions.