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Jadeite jade
The variety of jadeite pyroxene used as a gem
or ornamental material consists of microcrystalline aggregates
which. together with similar aggregates of tremolite-actinolite
amphibole (nephrite), come under the general name of jade
For reasons of clarity, we shall therefore be using the term
jadeite jade, rather than either jadeite or jade alone.
Appearance Jadeite jade is
a semiopaque to highly translucent aggregate of juxtaposed,
very firmly interconnected granular crystals. Only in rare
instances are there visibly elongated crystals, in fibrous
radiating or parallel groups. The general impression is not
so much of individual crystals as of a mass with a fairly
finely interwoven network of numerous, minute discontinuities.
These are the boundaries between one crystal and another or
the cleavage surfaces inside some of the crystals.
Despite this minutely fractured appearance,
the principal characteristic of jadeite jade is, in fact,
extreme tenacity and toughness. On the surfaces of antique
pieces in particular, one can see a similar network of small
discontinuities which keep the pieces from having a perfect
polish. On modern pieces polished with diamond powder, this
network is much less visible. Many different shades of green
are possible, the most valuable being emerald green. Jadeite
jade of this color is quite translucent and is called imperial
jade.
Other shades of light and bright green are
also very lively and attractive. Dark green is less common.
The most frequent color is semitransparent to nearly opaque
white, or off-white to very pale hazel; others are red (generally
of an orange or brown hue), yellow, light and often grayish
blue, gray, pink, and pale lilac. The brightest colors generally
occur only in zones or in blurred, fringed streaks within
the block. Pebbles recovered from alluvium often have an outer
layer of a brown color because of oxidation, that fades away
on the inside. It is used as a gem, cut into cabochons or
engraved stones for settings, beads, or other ornaments, especially
when the background color or limited patches of color are
an attractive shade.
Last but by no means least, jadeite jade, like
nephrite jade, is made into exclusive types of decorative
ware or small sculptures. Because of its tenacity, which is
almost equal to that of metals, generations of craftsmen in
the Far East have used it to produce staggering tours de force,
such as chains with unjolnted, individual links made from
a single piece of stone, thin-walled vases generally with
loose links on the handles and lids, cutting weapons (daggers
and parade swords), cups with engraved decorations, buckles,
and other finely pierced objects. Its other distinctive feature,
the presence of patches and streaks of bright color inside
and outside the uncutstones, has been skilfully manipulated
into wonderful multicolored pieces.
Typical examples are birds sculpted in such
a position and such a manner that a splash of orange on the
block of stone, for instance, serves to produce the beak,
a streak of green simulates the flight feathers of the wings,
an area of brown is used for the feet, and so on. Cups decorated
with brown-stemmed vine shoots, green leaves and fruit, and
colored flowers and butterflies are among the other prodigious
works of art that have been made from jadeite jade.
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