Source :
HONG KONG JADE ASSOCIATION
http://www.hkja.com.hk/
The Difference Between Jade and Jadeite
Jade stone itself is a gemstone from natural. In Chinese words, “the finest of stone is Jade”. The qualities of jade stone are hard and fine, and with uniform hue and color, and beautiful crystal-like shine. Jadeite is one of the jade stone’s forms. And so a jade stone does not necessary is a Jadeite. In Chinese, Jadeite is called “Fei Cui”. And this name is come from a bird’s name. This bird has a very colorful and beauty feathers. The male bird has red feathers, and it called as “Fei” bird. The female bird has green feathers, and it called as “Cui”. In combination, they called “Fei Cui”. There has wide range of variations in color of Jadeite. The color is mostly found in white, green, red, purple, blue, yellow, black and pink. | 
The Natural and different color jadeite |
The Difference Between Nephrite and Jadeite
Jadeite - adeite is a pyroxene mineral composition NaAlSi2O6 (the mineral must have more than 50% of sodium and aluminium-rich to qualify as Jadeite) and is monoclinic. Jadeite is formed in metamorphic rocks under high pressure and relatively low temperature conditions. It has a Mohs hardness of about 6.5 to 7.0 and dense in between 3.25 to 3.35 depending on the composition. Jadeite's color is largely affected by the presence of trace elements of chromium. It's commonly color ranges from white through jade green. And the most common color is pale green. The jade green is more valuable. The Nephrite has a longer history than jadeite. Today, the main exporting country of jadeite are Union of Myanmar (the world's largest jade exporter) , Guatemala, USA and Russia (only has a small amount of export).
Nephrite - The chemical composition of nephrite is the calcium and magnesium silicate (Ca2Mg5 (OH) 2 (Si4O11) 2),. It is monoclinic. It’s color is depends on the composition of amphibole and actinolite. The color of Amphibole mineral mainly is in white and grey. The color of actinolite is according to iron content and their degree of oxidation of iron level, and it can cause colors varies in dark green, reddish brown and black.
Nephrite is softer than the natural jade stone. High purity and texture is produced in Hetian from Xinjiang. It has a glass - oil sheen like shades. It proportion of minerals is in between 2.80 - 3.10, and Mohs hardness around 6 - 6.5. It’s color due to the presence of different mineral composition can present in pure white to mist dark and other colors. It is the toughness in jade stone and is not easily to damage. In addition, the community is popular so-called "China's four famous jade" which are Hetian jade, Turquoise, Xiuyan jade and Dushan jade. However, only Hetian jade and Xiuyan jade are truly belong to Nephrite in mineralogy. | 
Natural color jadeite
The different color nephrite |
The natural Jadeite Jade
The artificially treated jadeite jade
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Definition of Type “A”, “B”, “C” Jade
A Jade (Natural Jadeite Jade)
Refer to natural jadeite which is not subjected to any form of chemical treatment except processes such as colorless wax polishing are not defined as “treatment” on the crystalline structure of the jadeite jade, which has not been damaged.
B Jade (Jadeite jade has been artificially treated)
Refer to jadeite jade which is chemically treated and resin impregnated to enhance its translucency. The structure of jadeite is damaged through this treatment and it will lose its lustre once the polymer deteriorates with the lapse of time. In addition, "B" jade cannot withstand heat and pressure.
C Jade (Jadeite jade has been artificially dyed)
Jadeite of this kind is usually colorless or of very faint tone, and is therefore dyed to enhance its brightness. However, such artificial hue will fade in time.
B + C Jade (Jadeite jade has been artificially treated and dyed)
Refer to Jadeite jade has been dyed to enhance its translucency and brightness during the chemically treated, resin impregnated process.
Note: “A”, “B”, “C” jade are trade terms commonly used for Jadeite in the jade industry, not represent the grades and class or the quality of jade.
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Processing of Jadeite
There has a Chinese idiom called “jade is not polished and carved，not as valuable produc” means jade cannot be made into anything without being cut and polished. And that is absolutely true. To become a beautiful jadeite jade, it must undergo a series of treatment processes.
Choice of materials - According to the color direction, trace of marks, and the direction of the crackles on the raw material to determine the use of materials, and the size of the finished product.
Design of the shape -According to the shape, color patterns, thickness of jadeite, and the consideration of the current market demand to design the product shape.
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Cutting - Cut the stone according to the drawing lines in jade shape。
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Light embryo - Cut and sanding a rough shape to a designed figure
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Sanding - Sanding is a process to make the material surface lighter and smoother. The process is starting from large to small, from rough sanding to smooth sanding.
Polishing - Polishing is often used in leather surface. And there also has a polish powder, which mixed with water, can coat on leather and makes it half wet. And it is used to polish jade and makes it shine and bright.
Grey Acid - During the jade processing, oil stain and dirt may filter into the jade. And to remove the lipid and dirt from jade, first wash the jadeite in plum juice (organic acid) then put it in grey acid for few hours. After washing, lipid and dirt can be removed from jade and the process will not damage the jade inter-structure.
Stew wax or spray wax
The purpose of this process is to give jadeite a shine and smooth surface. There are two methods: Boiling wax – use a container for paraffin wax melting cooking after few hours until the wax can deep into the cracks or pores of the jadeite.
Steamed Wax — this method is for larger carvings. Placed the carvings in oven heated to 70oC-80oC degrees Celsius. Then steam the wax or put wax powder on the top.
Finally, cleaning and wiping the wax again. Use a towel or a bamboo stick to wipe the wax from the surface. That’s given a shine and smooth surface of the jadeite . |
How to evaluate jadeite values
There has many factors can affect jadeite values. Usually a jadeite value is determined by its structure, color, weight, integrity and quality of carving. Furthermore, the supply of raw materials and the brand effect can also affect the value of jadeite.
| The quality of jadeite can be evaluate in these 4 conditions: |
| 1. | Color - Color is the most important factor in evaluating jadeite values. The color of jadeite should be rich, completely even, and color pure. |
| 2. | Translucency – The best jadeite must have good translucency, a fine texture and high brightness, even in pale green to dark green. |
| 3. | Shape – the shape of jadeite, size, thickness, and the sanding works should be well mixed . |
| 4. | Clarity – the quality of jadeite is determined from its clarity. A fine jadeite should be free from noticeable or distracting defects, include cloudy patches, black spots, crackles or scratches |
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Maintenance
Wearing:
After collision and friction, jadeite can be dull or even damage. Therefore each single piece of jadeite jewelry should be stored separately in order to avoid collision and friction damage. And should be careful not to fall the jadeite jade when wearing.。
In hot summer days, a human body can be very sweatiness. Therefore should wash jadeite jade with cold water after wearing in order to prevent corrosion of sweat on the jadeite.
Use soap water for quick wash to remove surface dirt and oil. Then use a cotton stick with alcohol gently clean up. Finally, put it in a ventilated place to dry instead of sun exposure.
Not wearing:
If the jadeite is stored for a long time, recommend to soak it in cold water for few hours from time to time in order to retain its shine and glitter.
Avoid jadeite from heat and sun exposure if not wearing.
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