gems, peridot, olivine, Egypt, Zabargad, St. John’s Island

An analytical study by Nicolas-Louis Vauquelin of the gemstone known to contemporary jewelers as “chrysolite.” Vauquelin investigates its chemical composition in order to establish its mineralogical identity, finding it to consist principally of silica and magnesia with iron. The work helped characterize the mineral now known as olivine (gem variety peridot) and distinguish it from other yellowish-green stones to which the historically ambiguous name chrysolitehad been applied. The paper is an important example of the growing use of chemical analysis to resolve traditional gemstone nomenclature and establish mineral species on the basis of composition rather than color and appearance alone.