gems, general

De Barrera presents a popular but wide-ranging survey of gemstones and jewelry, combining their history, geographical sources, physical and chemical properties, valuation, cutting, trade, and use in personal ornament. Individual sections treat the principal gems—including diamond, ruby, sapphire, emerald, topaz, garnet, amethyst, turquoise, opal, pearl, and other ornamental materials—with accounts of famous specimens, historical traditions, mining localities, and contemporary commercial practices. The book also discusses methods of distinguishing gems, their hardness, specific gravity, color, and composition, together with imitation stones and aspects of lapidary work and jewelry manufacture. Drawing extensively on earlier mineralogical, historical, and travel literature, the volume provides a useful picture of popular and commercial gemological knowledge in Britain around the middle of the nineteenth century, before gemology emerged as a distinct scientific discipline.