A brownish-red mineral, a gemstone called carnelian, is cut and carved with modern tools in this 2009 video for a Carvers and Collectors: The Lasting Allure of Ancient Gems exhibition at the Getty Museum: The Art of Gem Carving. Gemstones such as amethyst, agate, chalcedony, jasper, lapis lazuli, and onyx have been engraved and etched with cameo (a two-color carving in relief) and intaglio (meaning “to cut into” from the Italian word intagliare) designs since antiquity. From Khan Academy:
Although intaglios are concave and cameos are convex, the ancient methods used to produce both were similar and, apart from the modern use of power tools, were much the same as those employed today.
The video above also shows how a scarab was carved on the back of the intaglio design:
In antiquity, engraved gems served as seals, amulets, or ornaments… However, the primary objective of an engraved gem was to serve as a seal for identification, much like a signature.
In the mid-500s B.C., the scarab design was introduced. A scarab is a gem with a curved back side, carved to resemble a dung beetle… This beetle was considered sacred in ancient Egypt; it was associated with the divine manifestation of the early morning sun.
Related reading: List of Gemstones By Name (A-Z).Related videos: The invention of graphics on cave walls, A Continuous Shape: Stonecarver Anna Rubincam creates a portrait, and installing massive statues with engineering and care at the Met.