The Jade trap.. To the uninitiated buyer the purchase of jade can be a
real problem and a trap.. Unfortunately there are unscrupulous and
uninformed merchants who are only interested in the dollar at the end
of the trail.
There is jadeite and nephrite jade which should be accepted as the
only true jades though each is a quite different material. I will
deal with the �imitations� first and then return to the true jades.
Serpentine sometimes called Korean Jade is widely sold as jade in
carvings, is not as hard as jade but is an attractive stone in its
Green aventurine quartz gets called jade
Green grossular garnet gets called �Transvaal jade�
Soochow Jade commonly seen as quite attractive figurines etc., is
glass from Soochow in China.
Californite can be called California jade.
Green idocrase sometimes get called jade.
Now to the real stuff. Nephrite jade , Hardness 5.5-6.5,
Na2Ca2(MgFe)10(OH2O2Si16044) and belonging to the amphibole family.
As you can see, a mixture of a number of minerals felted together and
in good quality nephrite making it a very tough stone which is
ideally suited for delicate carvings. Ranges through white, grey, all
shades of green and black. In New Zealand it is commonly called
�Greenstone�, the Maori called it �Pounamu� literally meaning �Waters
of greenstone� in reference I think to the rivers in which they found
the stone for use as mere, (a club), and for ornaments. I believe that
Nephrite jade was mainly used for carvings in China till the 18th
century when Jadeite was found in Burma and became part of the �Jade�
trade. Nephrite is found in China, Korea, Siberia, British Columbia,
Alaska, Wyoming, Australia and New Zealand. I believe it acquired the
name nephrite as it was at one time thought that if powdered and
taken it was a cure for nephritus. I could be corrected on that.
Jadeite� Hardness 6.5-7, NaAlSi206, and the Pyroxene family and the
structure is more like cryptocrystalline quartz (Agate etc) in that
it is a mass of minute crystals all jumbled together to make the mass
which incidently makes it quite easy to dye.. It come in many
qualities and colours ranging through white, the greens, orange and
red rarely, lavender and mixtures of these colours. Carvings in this
material are sometimes waxed after completion.
As a foot note I would advise you to be careful when setting nephrite
jade cabs as tripoli and rouge buffing will remove the stones polish.
Hope this helps you
Keith Torckler, Cornwallis New Zealand