Hardstone is a non-scientific term, mostly encountered in the decorative arts or archaeology, that has a similar meaning to semi-precious stones, or

gemstone A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, ...

s. Very hard building stones, such as granite, are not included in the term in this sense, but only stones which are fairly hard and regarded as attractive ones which could be used in jewellery. Hardstone carving is the three-dimensional carving for artistic purposes of semi-precious stones such as

jade Jade is a mineral used as jewellery or for ornaments. It is typically green, although may be yellow or white. Jade can refer to either of two different silicate minerals: nephrite (a silicate of calcium and magnesium in the amphibole group of ...

, agate, onyx, rock crystal, sard or carnelian, and a general term for an object made in this way. Two-dimensional inlay techniques for floors, furniture and walls include pietre dure, opus sectile (Ancient Roman), and medieval Cosmatesque work these typically inlay hardstone pieces into a background of marble or some other building stone. The definition of "hardstone" is not very rigid, but excludes "soft" stones such as soapstone (steatite) and minerals such as alabaster, both widely used for carving. Hard organic minerals such as amber and

jet Jet, Jets, or The Jet(s) may refer to: Aerospace * Jet aircraft, an aircraft propelled by jet engines ** Jet airliner ** Jet engine ** Jet fuel * Jet Airways, an Indian airline * Wind Jet (ICAO: JET), an Italian airline * Journey to Enceladus a ...

are included, as well as the

mineraloid A mineraloid is a naturally occurring mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amor ...

obsidian Obsidian () is a naturally occurring volcanic glass formed when lava extrusive rock, extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Obsidian is produced from felsic lava, rich in the lighter elements s ...

. Geologically speaking, most of the gemstones carved in the West are varieties of quartz, including chalcedony, agate,

amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος ''amethystos'' from α- ''a-'', "not" and μεθύσκω (Ancient Greek) / μεθώ (Modern Greek), "intoxicate", a reference to the belief that t ...

, sard, onyx,

carnelion Carnelian (also spelled cornelian) is a brownish-red mineral commonly used as a semi-precious gemstone. Similar to carnelian is sard, which is generally harder and darker (the difference is not rigidly defined, and the two names are often use ...

, heliotrope, jasper and quartz in its uncoloured form, known as rock crystal. On the Mohs scale of mineral hardness, quartz rates no higher than a 7, less for types with impurities. Stones typically used for buildings and large sculpture are not often used for small objects such as vessels, although this does occur. The term is derived from a literal translation of the Italian plural '' pietre dure'', 'hard stones', which in Italian covers all hardstone carving. The semi-anglicized singular '' pietra dura'' is used in English for multi-coloured stone inlay work, in fact using marbles as much as semi-precious stones, which was a Florentine speciality from the Renaissance onwards. ''Pietre dure'' is sometimes used for Italian or European vessels and small sculptures of the same period.See the introduction to the web feature o
''Art of the Royal Court: Treasures in Pietre Dure from the Palaces of Europe''
Exhibition at the Metropolitan Museum of Art

Notes

{{reflist Gemstones Visual arts materials Stones