gems, turquoise, chemstry

Reports a chemical analysis of oriental turquoise undertaken to determine its composition and clarify its mineralogical character. Hermann examines the proportions of its principal constituents and discusses the relationship between its chemical composition and that of other phosphatic minerals. The paper is of particular gemological interest as an early quantitative chemical investigation of turquoise and part of the nineteenth-century effort to establish the true chemical nature of this important ornamental gemstone.