GIADA. - A hard stone used in China in the industrial arts; it is composed of two silicates, nephrite and jadeite. The former is a silicate of calcium and magnesium, the latter of sodium and aluminum with iron silicate; both have notable hardness and a distinctive luster. Its color is generally green, ranging from light gray with greenish hues to very dark green.
It was used from the time of the most ancient dynasties
for small objects, mostly amulets, jewelry, and personal ornaments, but small votive statuettes, animal figures, and stylized flowers with complex symbolic meanings were also carved from jade. The working of jade was done using powders of harder stones, such as quartz and emery.
The use of jade in the West is scarce, but many ethnographic museums preserve interesting jade objects. In Italy, those in the museums of Florence and Bologna, as well as the Pigorini and Lateran Museums in Rome, are noteworthy.