The material Jade is actually made up of two different kinds of stone. The most widespread mineral in Chinese history is Nephrite, a variety of the mineral Actinolite and a Silicate of Calcium and Magnesium. It is composed of fibrous inter-twinned crystals. The other, more precious but less used mineral is the pyroxene Jadeite, a material composed of interlocking and very compact crystals. Chemically, it is a mix of Sodium and Aluminium Silicate NaAl[Si2O6]. Since 18th century, the better quality of Jadeite from Burma was introduced in the chinese market. The tough character of Jade that made it even stronger than steel was one reason for its widespread use in early civilisations in Europe, China and Meso-America.

Besides its toughness, the smoothness of the stone and the broad range of colours made it very attractive to early artisans. The basic jade colours and most valued are white or yellowish white and a colourless opaqueness. Inclusions of different metals give it the most beautiful colours like Chromium contents makes it emerald green (imperial jade), Iron makes it brown and green, Manganese creates violet colours. Calcium inclusions give it many different colours like white, apple Green, red, brown and even blue.

Jade was used in China to create many utilitarian and ceremonial objects ranging from indoor decorative items to Jade Burial Suits. Jade was considered the “Imperial Gem”. From about the earliest Chinese Dynasties until present, the Jade deposits were not only come from the region of Khotan in the Western Chinese province of Xinjiang but also from other parts of China, like Lantian. Shaanxi white and greenish Nephrite Jade is found in small quarries and as pebbles and boulders in the rivers flowing from thKuen-lun mountain range northward into the Takla-Makan desert  area. River jade collection was concentrated in the Yarkand, the White Jade (Yurungkash) and Black Jade (Karakash) Rivers. From the Kingdom of Khotan, on the southern leg of the Silk Road, yearly tribute payments consisting of the most precious white Jade were made to the Chinese Imperial Court and then transformed into Objets d’art by skilled artisans as Jade was considered more valuable than gold and silver.

Neolithic artisans used to shape the stones to Axes, Knives and Animals. A typical Chinese shape for jade objects are emblems like a Ring called Huan, a Half-ring Pendant named Huang, Axes called Yue, Fu or Chan, a round shape Disk called Biand square tubes called Cong.

The Shape, Size, Use and Meaning including the Symbolism of chinese jade objects, changed in the course of the millenniums and was respectively accompanied by a various meaning and valuation under the different Dynasties. In Ancient China, while attending conferences and negotiations, Court Official held their designated Jade objects in their hands to attain power, strength and wisdom.

Difference between Nephrite and Jadeite Jade:

Nephrite:

Milky soft colour stone Nephrite is a Silicate of Calcium and Magnesium. What distinguishes Nephrite from other rocks with the same chemical composition is its needle-shaped grains and tightly interwoven, fluted, fibrous structure. It rates 6 to 6.5 on Moh’s scale of Hardness. Nephrite is stronger than most steels and has waxy, fibrous texture. Nephrite comes in a variety of colours, including its most prized colour yellowish-white called “Mutton Fat,” long cherished by Chinese carvers and collectors. Without impurities Nephrite is snowy white. The vast majority of ancient Chinese Jade products were made of Nephrite. The presence of Magnesium and Iron produce a bluish white colour.Yellow is produced by Ferric Ion, brown by Hematite and grey and black by Graphite. Nephrite is more abundant than Jadeite and is found mostly in dolomitic marbles and Serpentised Ulramfics. It was first discovered by Chinese, who regarded it as very rare material and went through great trouble to obtain it. Today, it is found in many places, including China, Siberia, Taiwan, New Zealand, Alaska, California and Wyoming. Boulder-size deposits exist in British Columbia and Australia. According to the Guinness Book of Records, the largest piece of jade is a piece of nephrite found in the Yukon Territory of Canada that weighed 636 tons.

Jadeite:

Jadeite best known for the bright Green of the highly polished form that is favoured for jewellery is a Silicate of Sodium and Aluminium. It is generally shinier and slightly heavier and harder than Nephrite but not as tough. Jadeite rates 7 on Moh’s scale of Hardness as compared to 6½ for Nephrite and 10 for a Diamond which is the hardest substance on the earth. About 90 percent of the worlds Jadeite comes from Myanmar (Burma). There are additional small deposits of the Jadeite stone in Russia, China, Japan, and North and Central America. The first shipments of the Jadeite stone from Burma to China arrived in 1784, and has been greatly valued since then. The Ancient Chinese did not make a fine distinction between true Jade and Jade simulates. Common jade simulates fall into four classes: 1) Serpentine 2) Feldspar, 3) Carbonate and 4) Quartz Groups. Quartz group specimens, such as the transparent colourless rock crystal known to the Ancient Chinese as “Aqua-jade,” are the most observed form of Jade stimulant. Carnelian, known as “Red Jade” in Antiquity, is ideal for carving. Green Jadeite gets its green colour from the element Chromium. The most prized Jadeite is translucent, emerald green jade known as “Imperial Jade.”

Since Ancient China, the broad meaning of Jade stone covers not only Nephrite and Jadeite, it also includes Crystal, Agate, Serpentine, Marble, Turquoise, Lapis Lazuli and other varieties which are not jade; while the narrow meaning refers to the mineralogy of jade specifically, which is sub-divided as Nephrite (soft jade) and Jadeite (hard jade).