Semi-precious in the context of "Hardstone carving"

An engraved gem, frequently referred to as an intaglio, is a small and usually semi-precious gemstone 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; when referring to monumental sculpture, the term counter-relief, meaning the same as intaglio, is more likely to be used. Vessels like the Cup of the Ptolemies and heads or figures carved in the round are also known as hardstone carvings.

A cumdach (Old Irish pronunciation: [ˈkuβ̃d̪ax], in Irish "cover") or book shrine is an elaborate ornamented metal reliquary box or case used to hold Early Medieval Irish manuscripts or relics. They are typically later than the book they contain, often by several centuries. In most surviving examples, the book comes from the peak age of Irish monasticism before 800, and the extant cumdachs date from after 1000, although it is clear the form dates from considerably earlier. The majority are of Irish origin, with most surviving examples held by the National Museum of Ireland (NMI).

The usual form is a design based on a cross on the main face, with the use of large gems of rock crystal or other semi-precious stones, leaving the spaces between the arms of the cross for more varied decoration. Several were carried on a metal chain or leather cord, often worn off the belt, or suspended around the neck, placing them next to the heart and thus offering spiritual and perhaps medical benefits (the same was done with the St Cuthbert Gospel in a leather bag in medieval Durham). They were also used to bring healing to the sick or dying, or more formally, as witness contracts. Many had hereditary laykeepers from among the chiefly families who had formed links with monasteries.