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PRECIOUS STONES.
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a triclinic mineral of a beautiful blue colour. It contains in ioo parts about—
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,
if 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
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