History & Introduction
Jade is an umbrella term that represents a huge variety of gemstones, but the only
pure forms of jade are found as jadeite and nephrite. Jade was first used several
thousand years ago to make weapons and tools because of its toughness. The name
"jade" comes from the Spanish word "piedra de ijada", which means "stone for the
pain in the side". When the Spanish explorers noticed natives of Central America
the name came while holding pieces of jade to their sides, believing that it could
cure ills. According to the Chinese jade is named as "yu", which means "heavenly"
or "imperial". Therefore, in Chinese culture it is popular as the imperial gem.
In China, jade was found in the tombs of Shang kings.
Jade has a vital role in the history of New Zealand. It is available in South Island
and was treasured for number of years by the Maoris of New Zealand, who called it
as "pounamu", "greenstone" or "New Zealand jade". Pounamu was converted into Maori
tools such as chisels and fish hooks, and weapons like short clubs and ornaments.
This New Zealand jade is mainly a nephrite. Lake Baikal region of Russia spinach-green
nephrite is obtained known as "Russian jade". Between the two varieties jadeite
is the rarer, and the result it is more precious.
Recognise - As compared to other stones Jade is easily recognized
due to its hardness and density. There are many other materials fraudulently sold
as jade and it is difficult to recognize jade from its outside appearance. The reliable
method to identify jade from other substances is due to testing of its specific
gravity. A simple test is done to differentiate jadeite from nephrite is a chime
test. When the nephrite is struck it emits a musical tone, whereas jadeite does
not.
Availability - Nephrite is more common as compared to jadeite and
it is extracted from Brazil, New Zealand, Australia, China, Canada, Russia, Taiwan,
Alaska, Zimbabwe and Poland. The main source of jadeite is Myanmar (Burma), which
is also the only source of imperial jadeite. Jadeite is also found in Japan, Kazakhstan,
Turkey, Canada, Guatemala, Russia, Cuba and USA.
Usages - It is used in making traditional Chinese figures like
the Buddha, dogs, dragons, bats, butterflies, peaches and discs. It is even made
into all manner of practical items, like buttons, cups, plates and salt and pepper
pots. Besides these carving figures it is used to make beautiful ornaments like
the fashioned beads, cabochons for rings, brooches and fancy pendants and bangles.
Buying Guide
Color - Jade is available in various colors like white, green,
orange, lavender, yellow, grey and black. The rich emerald green is the most highly
valued and semi-transparent jade. It is known as imperial jade and is available
only in Burma (Myanmar). Jade is more than one color in a single gem and where the
distribution of color is highly valued. The inclination of color varies according
to the region. Like in the West, rich and deep green jade is given more importance.
However in Far East, pure white or yellow jade with a pink tone is preferred, along
with green imperial jade.
Clarity and Lustre - Jade luster is vitreous (glassy). It appears
vitreous to oily when polished. Jadeite is considered to be more vitreous (glassy)
luster than nephrite and carrying more resinous (oily) luster.
Cut and Shape - Jade is enormously versatile and can be carved
into complicated shapes. Rough jade is often bought as slices that gives no indication
of the quality of the material inside. The internal quality of the jade is unknown
until the rough stone is cut.
Treatment - Jade is frequently bleached with acid to erase the
brown pigments. Bleaching makes the jade porous and more prone to breakage, hence
after the bleach process the jade is mostly impregnated with a polymer that fills
the fractures and improves its appearance. A "Chelsea filter" is used to determine
whether jade is artificially dyed. When it is looked through this kind of filter,
then dyed jade will exhibit in red. The jade industry from China uses a grading
system to classify jadeite by the amount of enhancement it gets. As the system describes
grade ‘A’ jadeite is not dyed nor impregnated rather it may receive a coat that
is considered stable. For grade B jadeite may have been impregnated and bleached,
however it is not dyed. Grade C jadeite is dyed and impregnated, and grade D jadeite
is considered as not a real one.
Gemological Characteristics: