Jade; A Comprehensive Bibliography

Abstract

Nephrite is a silicate of calcium and magnesium, often containing small amounts of iron and is one of the amphibole group of minerals. It is distinguished by its structure, which is characteristically fibrous, and of such fine grain that the individual fibers are hardly visible. The fibers are variously arranged, parallel to each other, curved, twisted, fan-shaped, interlocked and felted in complicated fashion. Since the hardness is 6.5, and specific gravity close to 3, it fuses with some difficulty to a greenish glass and is not decomposed by hydrochloric acid. Nephrite is found abundantly on the west coast of South Island in New Zealand, where it occurs as boulders and sometimes as nodules and veins in serpentine and talcose rocks. Specimens appear also in New Caledonia and in some of the other Pacific Islands. Siberia has yielded very fine dark green nephrite, notably from the neighborhood of the Alibert Graphite Mine, near Batugol, Lake Baikal. Quarries in Karakash and Yarkand River valleys, Turkestan, have furnished much of the nephrite used by the Chinese. Switzerland, Alaska and British Columbia also yield pure nephrite. Jadeite is a silicate of aluminium and sodium, usually containing small quantities of iron, calcium and magnesium and is one of the pyrozene group of minerals. It has a vitreous luster, varying from translucent to opaque, and occurs very rarely in distinct crystals, but usually massive and closely compact. With a hardness of about 7 and specific gravity of approximately 3.3, it fuses readily to a clear glass and is not decomposed by hydrochloric acid until after having been fused. The chief supply of jadite, including the precious emerald green fei-ts'ui, comes from Burma, where it has been found in the several tributaries of the Irrawaddy River, and at Taumaw, Hweka and Mamon. It also occurs in Turkestan where nephrite is found, and other Asiatic localities. The most productive deposits appear to be in Belurtag, the jade mountain of the Chinese, on the upper waters of the Tishab River, near Yarkand. It is mined by Kachins and shipped to the lapidaries in Peking, Canton and Shoochow, the chief centers of the jade industry today. The finest jade carvings were made in the imperial ateliers at Peking. Objects of jadeite are common in Mexico, Central America and in the northern part of South America. At the time of the Spanish conquest of Mexico amulets of green stone were highly vener. ated, and it is believed that jadeite was one of the stones prized under the name of chalchihuitl. Chloromelanite may be regarded as a variety of jadeite rich in iron, often containing as much as ten per cent. It is spinach-green or dark green in color and has a specific gravity of 3.4. It occurs in the Cyclops Mountains in New Guinea, where natives make hatchets and agricultural implements from it. Celts made from this mineral were found in the dolmens of France and in certain ancient Swiss lake-dwellings. Jadeite and nephrite have so strong a resemblance to each other that their true identity must be ascertained by microscopic examination and chemical analyses. Their differentiation becomes more difficult when the two substances occur in the same specimen, the nephrite having been formed from the jadeite by a gradual alteration of its chemical and physical constitution. Jade minerals are white when pure, but in nature they are more often variously colored. A partial jade spectrum is given by John Goette in Jade Lore (1937). Their range is from white to black through varying shades of green, yellow and red. Black jade nephrite, which is rare, contains chromic iron. Usually it is of dull color with whitish toned flecking. Red and brown tones in jade are due to inclusions of iron pyrites. Yellow jade, which is also quite rare, often has a light greenish tinge. The shades of green vary from