inclusions, microscopy, gems

ruby, sapphire, corundum, Burma.12, jade, jadeite, fei cui, gems

Sinkankas: Both articles based on author’s many gem-buying trips and with photos taken by himself; describes geography, transport, the people, mining of gemstones, geology of deposits, mineralogy, history, recovery of jade and amber, mines, and gem trading. Obit. American Mineralogist, 59, 1974, p. 1870. Mining. [414].

corundum, ruby, sapphire, synthetic corundum.7, synthetic ruby, synthetic sapphire, gems

Chudoba and Gübelin provide a practical guide to distinguishing natural gemstones from synthetic counterparts, combining a short history of artificial gem production with detailed discussion of the principal manufacturing methods and their diagnostic consequences. The Verneuil flame-fusion process, flux growth, and hydrothermal synthesis are described, together with the characteristic structures and inclusions they produce. Particular attention is given to synthetic ruby and sapphire, spinel, emerald, and other important gem materials, with comparisons between natural and laboratory-grown stones based on growth zoning, curved striae, gas bubbles, mineral inclusions, refractive properties, fluorescence, and other microscopic and physical features. The authors emphasize examination with the gemological microscope as one of the most powerful means of separation, supported by numerous photomicrographs illustrating inclusions and growth phenomena in both natural and synthetic gems. Conceived as a concise working manual for gemologists and jewelers, the book brought together the principal identification criteria then available at a time when synthetic gemstones were becoming increasingly sophisticated and commercially important.

jade, jadeite, fei cui, California, gems

ruby, sapphire, corundum, Burma.12, gems

Reports on a visit to Mogok and its surrounding gem fields in autumn 1955, describing travel conditions, mining and the local gemstone industry. Lists the gem minerals recovered and explains traditional cutting practices and bargaining by concealed hand signals beneath a cloth. Also warns of synthetic corundum tumbled to resemble natural ruby rough.

corundum, Australia.12, gems

gems, jade, jadeite, fei cui, Mesoamerica, Mexico, Guatemala, Costa Rica, Mayans, Olmecs, Aztecs, archaeology, history, archaeogemology

Costa Rican jade ornaments have been known chiefly through collections made by Padre José Maria Valasco in the Nicoya peninsula, which forms the northwestern corner of the country, and through the subsequent publication of these specimens by C. V. Hartman (1907). The Velasco jade is now in the Museo Nacional at San José and the Carnegie Museum of Pittsburgh.The term jade is loosely used by archaeologists. Hartman employed it to describe 3 minerals: a blue-green jadeite, saussurite, which in Costa Rica usually is blue-green with white spots, and a dark green bowenite. These shades are characteristic of Nicoya specimens but not of the jades of northern Central America and Mexico. More recently, W. F. Foshag has identified the principal minerals used for ornaments in Costa Rica as diopside-jadeite and chalcedony (Anonymous 1947, Specimens 1-7, 15-18).

gems, amblygonite

corundum, ruby, sapphire, inclusions.5, phenomena, star, gems

gems, gems, jade, jadeite, fei cui, Mesoamerica, Mexico, Guatemala, Costa Rica, Mayans, Olmecs, Aztecs, archaeology, history, archaeogemology, Pre-Columbian jade; Costa Rica; Maya; exchange; iconography, lapidary

Studied numerous smaller jade carvings in order to establish lapidary methods, as illustrated by the pen-and-ink drawings. Discusses the jades of the Maya culture and those of the Valley of Mexico and Oaxaca, together with excellent Olmec objects from the La Venta culture. Features excellent drawings; photographic plates consist mainly of jade carvings.