Definition of chalcedony in English:



  • [mass noun] A microcrystalline type of quartz occurring in several different forms including onyx and agate.

    • ‘Calcite and barite actually crystallize after the formation of chalcedony and quartz cease and often infill or possibly cause subsequent fracturing of the agate.’
    • ‘Vein minerals are barite, calcite, chalcedony, and quartz.’
    • ‘The collection today has eight vases executed by the Baroviers in calcedonio glass, which imitates chalcedony, banded agate, and other semiprecious stones.’
    • ‘In the spring of 1968, Stepanov together with amateurs B. Kantor and E. Kurdyukov discovered the now-famous manifestation of hollow agates with chalcedony pseudostalactites in the Moscow region.’
    • ‘Other minerals mentioned from the mine by Dunham include galena, sphalerite, pyrite, chalcedony, and minor marcasite and pyrrhotite.’
    • ‘Common cements include clay minerals such as kaolinite, montmorillonite, or illite; quartz or chalcedony; iron oxides such as haematite; or calcite.’
    • ‘The coarsely crystalline veins are composed predominantly of colorless barite and quartz and white chalcedony.’
    • ‘The Brushy Basin sediments contain numerous chalcedony pseudomorph-after-barite concretions that range to more than 30 cm in diameter.’
    • ‘In fact, seventeen of the fifty-seven sites are specifically listed for agate, chalcedony, chert, jasper, or petrified wood.’
    • ‘Concretions of chalcedony after barite can be confused with cycads, and the wise collector must learn to differentiate between the two.’
    • ‘These include Neolithic tools made from chalcedony as well as nephrite objects from Ancient China.’
    • ‘The matrix is composed of microgranular quartz with some fibrous chalcedony.’
    • ‘The depictions of birds and flowers were executed in precious materials including lapis lazuli, agate, Sicilian red and green jasper, chalcedony, amethyst and quartz as well as superb hard stones.’
    • ‘The fine-grained sediment of the matrix is composed chiefly of microgranular quartz, although chalcedony with a fibrous texture is sometimes found.’
    • ‘Heaney expected to find that the quartz in tiger's-eye was chalcedony, a form that typically consists of fibrous, defect-riddled crystals less than 1 micrometer in diameter.’
    • ‘Slowest-forming and most beautiful of all, huge crystals of amethyst, agate, chalcedony and rock crystal grow where condensed water has managed to seep into naturally insulated rock crevices.’
    • ‘Groutite is observed as small, lustrous black, acicular crystals to 1/8 inch long that occur directly on the quartz or chalcedony.’
    • ‘The shoots and stalks themselves are casts composed of combinations of chalcedony, quartz, calcite, and barite.’
    • ‘Furthermore Oehler had previously shown that the silica minerals quartz and chalcedony critically important in the petrification of wood, can be made, rapidly in the laboratory from silica gel.’
    • ‘The former habit is best known as the diagnostic morphology exhibited by stilbite; the latter is seen in many minerals, from malachite to chalcedony to goethite.’


Late Middle English: from Latin calcedonius, chalcedonius (often believed to mean ‘stone of Chalcedon’, but this is doubtful), from Greek khalkēdōn.