Three-pronged plaque with animal masks

Look carefully at the design incised on the surface of this small plaque. The animal it represents might be the predecessor of the one depicted in monster masks (taotie) found on vessels of the early Bronze Age. Jade has been worked longer in China than anywhere else in the world. Going back more than seven thousand years, since before 5000 BCE, jade has been made into symbolic and ritual objects used in daily life and burials. The earliest Chinese dictionary, compiled some two thousand years ago, lists more than a hundred characters referring to the nature of jade. In its narrowest definition, yu (玉), the Chinese word for jade, refers to two distinct types of stones: jadeite and nephrite. In its broadest definition yu also includes serpentine, quartz, and many other gemstones.

Attesting to an old saying that unworked jade will not reveal its true value, the working of jade requires tremendous and intensive manual labor, time, and skills. Most types of jade are too hard to be worked directly with metal tools such as chisels or knives. Nephrite is composed of dense mats of relatively long fibers, making it a tough stone that has a high resistance to breaking or chipping and finishes to a soft glow. Jadeite, made of shorter fibers, is harder than but not as tough as nephrite; jadeite has a resistance to scratching or abrading and finishes to a bright shine. In their pure states, both stones are white and semitranslucent. The broad range of hues and tones seen among jade objects is the result of various chemical impurities inherent in the materials.