calcedon

Noun

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.
   • 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.1932, United States. Department of the Treasury, Treasury Decisions Under Tariff and Internal Revenue Laws, page 1673
   • A yellowish-red carnelian is a calcedon. Is found–among other places–in India. […] Like carnelian, agate is a calcedon.1941, Nationalmuseets skrifter: Etnografisk raekke - Volumes 7-8, page 196
2. The bass lute, an instrument used by baroque composers (notably Telemann).
   • 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.1985, University of North Carolina at Chapel Hill. Music Library, “The Plot Thickens”, in Notes from the Hill, page 14
   • 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.1995, Daniel R. Melamed, “Performance questions in Bach's Trauerode”, in Bach Studies 2, page 139