gems, jade, Fischer, Naldi

This French translation of Wallerius’s influential Mineralogia presents an early systematic classification of the mineral kingdom, dividing it into earths, stones, minerals, and concretions, followed by preparations made from mineral substances. Minerals are distinguished through their composition, form, colour, transparency, hardness, specific gravity, geological occurrence, and behaviour under heat or chemical treatment. The extensive treatment of stones includes nephrite, rock crystal, agate, chalcedony, onyx, opal, jasper, lapis lazuli, and numerous ornamental materials. Precious stones are discussed separately, including diamond, ruby, sapphire, topaz, emerald, chrysolite, amethyst, garnet, hyacinth, and aquamarine. Wallerius describes their varieties, crystal forms, relative hardness, colours, host rocks, geographical sources, and response to fire, while also addressing false or coloured crystals, methods of artificial staining, and means of distinguishing genuine stones. Although many identifications and mineral relationships are now obsolete, the work represents an important transition from traditional lapidary nomenclature toward the systematic classification of minerals by observable physical and chemical properties.