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- Yarkand), in Siberia near Lake Baikal, in Taiwan, New Zealand, Australia, parts of North America, Rhodesia and in parts of Europe, namely Poland and Italy. Jadeite can be found in Burma, Guatemala, parts of North America, Japan and the East Indies.
Nephrite, which is composed of calcium magnesium silicate, is fibrous, very resistant to fracture, and is almost waxy in appearance. On the other hand, jade- ite, which is silicate containing sodium and aluminum, is more easily broken, and when polished produces a brilliant, gleaming surface.
It is said that jade comes in every shade of the rainbow. The wide variety of col�ours found in jade is due to the presence of different proportions of minerals. If there is an absence of minerals, pure nephrite or jadeite should be white. The pre�sence of iron gives green colour to nephrite, while it is chromium that makes jade�ite green.
In China, during the Jin dynasties (265-420), the Jade Records classified jade into nine colours and the mixes; black as in deep water, blue as in indigo foam, green as in fresh moss, emerald as in kingfisher�s feathers, yellow as in steamed chestnuts, vermillion as in cinnabar, purple as in congealed blood, jet black as in ink, white as mutton fat and mottled with red and white streaks.
A more recent account says good jade comes in these colours: ruby red, chicken- blood red, cinnabar red, cherry red, date red, parrot green, pine-needle green, gingko green, osmanthus fragrus yellow, sunflower yellow, chestnut yellow, wine yellow, fishmaw white, chickenbone white, rice white, pool-water grey-blue, crab- shell grey-blue, willow green, bamboo leaf green, eggplant purple, palm hair pur�ple, bean paste mauve, pure varnish black and old ink black.
Generally speaking, it is felt that the pure colours are superior, whereas mottled and mixed colours were regarded as less precious. It seems that pure white jade was the most preferred throughout Chinese history, but yellow jades were very popular during the Ming period.3
Another way in which jades can acquire colour is by use of artificial means. Jade workers during the Qing dynasty and modern day dealers have been known to stain jades in order to give the desired colour or to give them an appearance of age. (See discussion on making copies of ancient jades in Appendix II.)
Both nephrite and jadeite are extremely hard. On the Mohs scale of hardness, nephrite is 6.5 and jadeite 6.75 (diamond, the hardest mineral, has a hardness of 10). Since steel is not more than 6.5 on the Mohs scale, it cannot be used by itself to carve jade. The word �carved� is somewhat misleading for jade, as the even�tual shape of the object is not achieved by carving, but by a slow process of grind�ing down the jade-stone with abrasives such as crushed garnet and quartz sand, which have a greater hardness than jade. The Chinese call this process zhuo or zhuomo, which does not have an equivalent word in English. In ancient China, abrasives were used in conjunction with tools made of wood, bone, bamboo and stone to cut, saw, carve, incise, and drill into jade. By the Erlitou phase of the Xia culture (nineteenth-sixteenth century B.C.), bronze tools were in use for working with jade. These included the wire saw for cutting, rotary point and tube for drilling, and rotary disc for grinding. The rotary disc may have been projected on a shaft which is called tazi and operated on a bench with a treadle.4 Iron rotary tools were introduced by the late Zhou around the sixth or fifth century B.C., and this equip�ment would remain the basic method of working jade for the centuries to come. After this, there appear to have been few major innovations in the technology of jade working until modern times, except that harder materials such as agate and corundum were brought into use as abrasives. These abrasives would be used
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