calcedon

See chalcedony.

calcedon (plural calcedons)

1. (dated) Any common mineral, such as chalcedony or calcite, that is found as an intrusion or vein in another stone, especially in a precious stone.
   • 1932, United States. Department of the Treasury, Treasury Decisions Under Tariff and Internal Revenue Laws, page 1673:

     Merchandise invoiced as calcedon, classified at 60 per cent ad valorem under paragraph 1528, tariff act of 1930, is claimed to consist of imitation semiprecious stones, faceted, dutiable at 20 per cent under the same paragraph.

   • 1941, Nationalmuseets skrifter: Etnografisk raekke - Volumes 7-8, page 196:

     A yellowish-red carnelian is a calcedon. Is found–among other places–in India. […] Like carnelian, agate is a calcedon.

   • 1980, Carl Heinrich Merck, ‎Richard Austin Pierce, Siberia and Northwestern America, 1788-1792:

     It consisted of small, rounded rock-boulders with calcedon and pieces of jasper.

   • 2005, Literature Criticism from 1400 to 1800, page 30:

     No part besides must of they selfe be known. But by the topaz, Opal, Calcedon.

2. The bass lute, an instrument used by baroque composers (notably Telemann).
   • 1985, University of North Carolina at Chapel Hill. Music Library, “The Plot Thickens”, in Notes from the Hill, page 14:

     In this, the final chapter of the "Calc." saga, it can be stated that the that the abbreviation in question really does stand for calcedon, a theorbo-type instrument.

   • 1995, Daniel R. Melamed, “Performance questions in Bach's Trauerode”, in Bach Studies 2, page 139:

     Indeed, the calcedon seems principally intended as a reinforcement to the cello: where the cello and keyboard parts differ from one another, the calcedon goes with the bowed instrument.

   • 2000, Per Kjetil Farstad, German Galant Lute Music in the 18th Century, page 354:

     At another private concert at Count Caldarinii's house in Bologna (1715), Caldarinii played alternately the lute and the calcedon.

   • 2020, Albert R. Rice, The Baroque Clarinet and Chalumeau, page 143:

     Christus is um unsrer Missetat willen, TVWV 1:151, 1721, scored for soprano, alto, tenor, and bass, two violins, viola, cello, organ, two oboes, two D clarinets, calcedon (bass lute), and organ.

While some authors seem to use the term calcedon as a synonym for chalcedony, others clearly distinguish it in some cases from chalcedony, and use the term to refer to other types of intrusions.

• conceal'd