gems, olivine, peridot, China

Describes gem-quality peridot mined near Damaping, China, since 1979, where crystals occur in nodules within Tertiary basalt flows. The material is compared in quality with peridot from San Carlos, Arizona. Reported refractive indices span 1.652–1.690, with birefringence of 0.034–0.036 and specific gravity of 3.34–3.36. Internal features include fingerprint-like healed fractures, lily-pad inclusions, and subtle growth irregularities.