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PRECIOUS STONES.

a triclinic mineral of a beautiful blue colour. It contains in 100 parts about—

Alumina 62·8 Silica 37·0 Iron oxides 0·2

Jade and Jadeite.

Under the name of jade (a falsely coined word derived through the French from the Spanish piedra de hyada) two distinct minerals are included. One of these, the commoner of the two, is also lighter and softer, and belongs to the species known as hornblende or amphibole; to it the name jade (or perhaps preferably nephrite) should be confined. It is a compact mineral consisting of irregularly interwoven acicular crystals of the sub-species actinolite. Its surface when polished acquires a soft greasy lustre; its substance, though remarkably tough, is easily scratched by rock crystal. Jade presents a variety of hues ranging from a rather creamy white through a number of tones of greyish and leaf-green to a deep or blackish green. An ochre-tinted jade also occurs, as well as examples in which browns and reddish browns, due to ferric oxide and ferric hydrate, make their appearance. The dark grey and blackish varieties contain inclusions of chrome iron. But whatever the colour of jade it is always translucent, never transparent on the one hand nor opaque on the other. Of its many varieties perhaps the green of New Zealand and the white or greenish white sort from Eastern Turkestan are the most familiar to Europeans.

Jadeite is as tough as jade, and takes the same polish, but it is much rarer as well as harder and heavier. Moreover it often presents, even to the unaided eye, an obvious crystalline texture, while the most esteemed variety is of a brighter and more emerald like green than any jade. Some specimens show in parts a delicate lilac tinge. It is from Burma that the jadeite worked by Chinese lapidaries comes. It is never found in such large masses as those in which jade occurs, but is sometimes of sufficient