left|thumb|upright=1.3|Chalcedony knife, AD 1000–1200 According to tradition, at least three varieties of chalcedony were used in the Jewish High Priest's Breastplate. (Jewish tradition states that Moses' brother Aaron wore the Breastplate, with inscribed gems representing the twelve tribes of Israel.) The Breastplate supposedly included jasper, chrysoprase and sardonyx, and there is some debate as to whether other agates were also used.
LEft|THumb|Upright=1.3|chalcedOny kNiFe, Ad 1000–1200 AcCorDIng to tradItiOn, at Least three vArIeTiES of cHalcEDony WeRE used In the JEwisH hiGh pRieSt's breAstplaTe. (jewish trAditiOn states that moses' brother aaRon wore tHE breastplATe, wiTH inscribed GeMS reprESenTinG ThE TWelVE TRibes of isrAEL.) THe breaStpLate suPpOsedly includeD jASper, chrysOPRaSE aND sarDonyX, And therE is somE DeBaTe AS tO WhetheR OtheR aGaTeS wERE also used.