Gem of the Month
Each month this section will feature
either a topic of interest to gem lovers or one special gemstone with
background on the material and its value.
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Revised and Updated: July,
2005
Jadeite Jade
Not recognized until 1863 as two
separate minerals, jadeite and nephrite: aggregate minerals that
overlap in color and transparency and have been used for tools and
art objects throughout history, are both called "jade". In most
instances, jadeite is the more valuable member of the pair,
especially in its highest quality where the price per carat can rival
fine emeralds and diamonds. The granular, interlocking pattern taken
by the tiny crystals in the aggregate accounts for its exceptional
toughness enabling it to have been used both for tools with strength
greater than most metals, and at the same time for the most delicate
of carved artworks.
[Highly translucent,
white and light green Burmese jadeite forms the delicate flower
petals and leaves of this 1920's vintage Chinese
artwork.]
We usually associate jadeite with
China, but that connection (which is undoubtedly major) is fairly
recent. Throughout the several thousand year history of Chinese use
and veneration of jade, it was nephrite which was the focus. Jadeite
has supplanted nephrite in the "hearts and minds" of the Chinese in
only in the last 200 years or so, since the time it first began to be
imported there from Burma. Burma is still the major world source,
especially for the finest material, but Guatemala, Russia, Kazakstan,
Turkey and the US (California) also contribute.



[Jadeite from around
the World: yellow Burmese fish carving, purple Turkish cabochon,
vivid green Kazakstani cabochon, California jadeite
tablet]
Jadeite can be semi-transparent to
opaque and covers the spectrum from colorless through white, green,
yellow, brown, red, orange, violet, to grey and black in color. In
general, the color range and saturation values are greater than with
nephrite, as is the maximum possible degree of translucency. Some of
the colors are given folk or trade names such as Imperial, apple
green, moss in snow or chloromelanite. Imperial is the variety with
the most highly saturated green color, apple green has some yellow,
spinach green is darker and less vivid than Imperial or apple green,
moss in snow has patterns in white and green, and chloromelanite is
such a dark green as to appear black. Various combinations of
chromium and iron are responsible for the different
colors.


["Shades of Green":
apple green ring, spinach green earrings, moss in snow
cabochon]
Well polished pieces have a "patent
leather" shine, but considerable lapidary expertise is necessary to
produce it. Jadeite sometimes frustrates lesser cutters with its
tendency to undercut, which can create a dimpled or "orange peel"
surface.
Most of the jadeite in the commercial
jewelry market has been enhanced through some combination of heating,
bleaching, dyeing or resin impregnation. It's generally easy to spot
such treatments as the stones look too uniform and saturated in
color, whereas all but the very highest grades of natural color
material show some mottling of lighter and darker and more or less
translucent zones. Reputable vendors designate three grades of jade:
"A" jade, which has had no color enhancing treatment of any kind, "B"
jade, which has been bleached or acid treated to remove dark spots
and resin impregnated to fill the resulting voids, and "C" jade,
which has been resin impregnated and then dyed. It is relatively
common for jadeite, even in top grades, to have been given a surface
polish with a layer of colorless paraffin wax.
Jadeite of inferior color is usually
dyed, while that of decent color but with unattractive inclusions is
subjected just to the bleaching/resin process. ACS sells only "A"
jade, but if you look around most of the mass market venues: trade
shows, catalogs, home shopping channels, online auctions, etc. you
will see B and C jade in abundance -- in fact you will rarely, if
ever, see A jade.
The ubiquitous presence of brightly
dyed and othewise enhanced jades has in some eyes diminished the
beauty of the more subtle colors of natural jades, and leads some to
question the much higher costs associated with the "real
deal".

[Two perennial "A"
jadeite favorites in my personal jewelry collection]
Fine chrysoprase is sometimes used as a
jadeite simulant, and in its best grades has been successfully passed
off as apple green, and even Imperial green jadeite. Aventurine and
serpentine are also common natural simulants. An early and still used
man-made imitation of jade, is glass, which can usually be revealed
by the presence of microscopic bubbles (which would never be seen in
real jade). Jadeite has just recently been synthesized (by General
Electric Laboratories, a leader in making synthetic gems for
research), but lab created stones have not yet made an entry into the
gem marketplace.


[Jade?: chrysoprase
cabochon, aventurine quartz Buddah, 10x view of glass jade imitation,
showing bubbles (image courtesy of Martin Fuller)]
Due to its superior toughness, natural
jadeite can be used for any jewelry application and needs no special
care in cleaning or wearing. It can be scratched, though, by harder
gems like sapphire or diamond and so, as with any fine jewelry,
pieces should be given their own separate "berth" in your jewelry
box. Dyed or resin impregnated pieces may fade or discolor with time.
Value Considerations
By far, the most valuable variety of
jadeite is that termed "Imperial". The finest of these gems are
nearly transparent and have the most highly saturated, even, green
color, rivaling (some would say surpassing) the finest emeralds. Such
pieces are extremely scarce and astronomically expensive -- the name
derives from the time when only the Imperial household was permitted,
and could afford to own it. Among the other green colors, the next
most valuable shade is termed "apple green". Fine, translucent,
lavender pieces can rival good greens in price, whereas highly
mottled or opaque gems are worth considerably less. Cholormelanite
has some value as a scarce collector material. As with nephrite, much
of the value in jadeite works of art comes from the skill with which
they were carved or the antiquity of the pieces. Enhanced material is
very modestly priced.
Gemological Properties:
Makeup: Pyroxene:
NaAlSi2O6
Hardness: 6.5 - 7
Toughness: exceptional
RI: 1.66 - 1.68
Density: 3.25 - 3.36
Polish Luster: greasy to
vitreous
Birefringence: .012 - .020
Stones Currently Available:
{Search
our Catalog}
Go to: Homepage
-- what's new in faceted
gems -- what's new in
designer cabochons and gem carvings --
gem of the month --
gem of the month archive --
birthstone of the month --
key to all the codes used on the ACS
site -- definitions of
terms used on the ACS site
-- how to order
-- about ACS --
about the ACS cutters --
settings for these gems
--faceting information
-- purchase UltraTec
equipment
-- Mail to
bsmigel@cox.net