“ Yukimoto sells Jadeite in type A.”
The variety of jadeite treatments result in a variety of jades in the market. The first type of jadeite is type A jadeite. Type A jadeite jade is completely natural and is the most valuable and rarest type of jade. Type A Jadeite Jade is accepted in the market as untreated jadeite-jade that has no polymer impregnation. It is considered a natural product even though most goes through a traditional cleaning and waxing treatment process. They can range from opaque to near transparent and can have fine to coarse texture appearance. Type A natural jadeite means that the subject qualifies to be free of any form of chemical treatment.
As part of the polishing process, coating the jadeite with colourless wax is accepted so long as it does not damage the crystalline structure of the subject. After fine polishing, the jadeite item is dipped in heated wax of liquid form and once cooled down it is buffed to give a smooth lustrous look. Waxing helps the jade to maintain its lustre by preventing body oils, sweat and dirt to enter its porous surface. The colour of the jadeite is natural and remains unaltered. Polished jadeite has a glassy, vitreous, vivid lustre.
Type B jadeite means the jade piece has been chemically treated by soaking in acid; which removes impurities or oxidation stains producing a “bleaching” effect, and thereafter strengthen with polymer material before fashioning. The process changes the colour of the jadeite in a lighter manner and leaves many holes or micro craters inside throughout jade piece. The bleached jadeite becomes porous and brittle, called ‘chalky’ jade in trade, and polymer filler is then necessary to strengthen the bleached jadeite and to improve its transparency. It is then placed into a vacuum chamber where polymer resins are infused into it. Upon a final polish to treat the jadeite coated with resin, it will look finished with a smooth and lustrous colour. Unfortunately, the colour of Type B jadeite will deteriorate over time and turn yellow due to the polymer resin oxidising when exposed to heat and sunlight.
For the type C jadeite, it has undergone all the treatments of type B in addition to the dyed colouring added on to the polymer resin to produced an enhanced colour. The dyeing agent is usually introduced into the jadeite via the grain boundaries or surface reaching fractures. Prior to the dyeing process, the jadeite is thoroughly cleaned and subsequently heated to expand the grain boundaries before it is dyed. Commonly, the dyeing process is performed to enhance green, lavender, yellow or red jadeite. The dye will fade over time due to a reaction with sunlight or body oils.
Left: A close-up of the natural green area shows a smooth, diffused color texture; field of view 7.19mm. Right: A close-up of a dyed area shows color concentrations in the thin gaps between the crystal grains of jadeite; field of view 3.57mm. Photos by Jonathan Muyal. © GIA.
Top: A close-up of the natural green area shows a smooth, diffused color texture; field of view 7.19mm. Bottom: A close-up of a dyed area shows color concentrations in the thin gaps between the crystal grains of jadeite; field of view 3.57mm. Photos by Jonathan Muyal. © GIA.