gems, tourmaline, Ceylon, Sri Lanka

A comparative chemical investigation by Nicolas-Louis Vauquelin of stones then called “hyacinths” from Ceylon (Sri Lanka) and Expailly, near Le Puy-en-Velay in France. By analyzing specimens from the two localities, Vauquelin sought to determine whether materials grouped under the same traditional gemstone name were chemically identical. The study is particularly important in the history of mineralogy because “hyacinth” was an ambiguous name applied to differently colored stones, including varieties of zircon. Vauquelin’s work illustrates the increasing use of comparative chemical analysis to resolve traditional gemstone nomenclature and distinguish mineral species that had previously been classified largely by color and appearance.