[Illustration: This emerald green jadeite carving, dating from the Ch’ien-lung period (1736-1795), stands 6½ inches without the base. It was given to the Smithsonian as part of the Maude Monell Vetlesen collection.] Jade is not particularly hard (6½), but it is very tough, and this characteristic makes it an excellent material for carving. Even when subjected to punishing usage, jade resists chipping and wear. It was used for making tools and weapons by primitive peoples who lived in what is now Mexico, Switzerland, France, Greece, Egypt, Asia Minor, and in other places. The jade implements fashioned by these peoples have survived well the ravages of time. The Chinese and Japanese prize jade highly. In their countries, tradition has assigned to jade medicinal and spiritual values, and has associated with it the cardinal virtues of charity, modesty, courage, justice, and wisdom. As a consequence, these peoples long ago developed the carving of jade as a high art. Among the magnificent Chinese jade carvings in the National Gem Collection are 130 pieces produced mostly during the Ching Dynasty (1644-1912), when the art of jade carving was at its peak. Many of these jades were carved in imitation of the revered bronze ceremonial vessels of ancient times. This collection was presented to the Smithsonian Institution in 1959 by Mr. Edmund C. Monell in behalf of the estate of his mother, Mrs. Maude Monell Vetlesen of New York. [Illustration: This pale green jade vase of the Ch’ien-lung period is 14½ inches high without the base. It is one of a matched pair presented as part of the Maude Monell Vetlesen collection of carved jade.] CHARACTERISTICS OF SOME COMMON GEMS Approximate average of (1) hardness (2) specific gravity (4) Dispersion (3) refractive index (5) Durability Species (1) (2) (3) (4) (5) Usual color range