Jade

Jade has been known for more than 7000 years. The name jade goes back to the time of the Spanish conquest of Central and South America and derives from "piedra de ijada," hip stone, as it was seen as a protection against and cure for kidney diseases. Because of its beneficial effect on the kidneys, the stone was also known as "lapis nephriticus". It wasn't until 1863 that mineralogists in France discovered that jade consists of two separate, distinct minerals, jadeite and nephrite. Jadeite is very tough and resistant because of its tight growth of tiny interlocking grains. Nephrite, a variety of the mineral actinolite, is even tougher, due to its composition of fibrous crystals inter-twinned in a tough compact mass.

The toughness of jade is remarkable. It has strength greater than steel and was put to work by many early civilizations for axes, knives and weapons. It was only later that jade became a symbolic stone used in ornaments and other religious artifacts. Today jade is highly valued for its beauty. Its many colors are appreciated, but it is the emerald green color of jadeite that is highly sought after by collectors. As jewelry stone, jade is used for pendants, necklaces, bracelets, rings and earrings.

Jadeite displays hues which include green, white, pink, red, black, brown and violet. Nephrite ranges mainly from mid to dark green or grey-green, but it can also be white, yellowish or reddish. Only in the very finest jade is the color evenly distributed. The emerald green jade called "Imperial Jade" is colored by chromium. Other colors are influenced by iron (green and brown) and manganese is thought to produce the violet colors. Nephrite is usually only green and creamy white, while jadeite can have the full range of colors. Russian jade is the trade name for spinach-green nephrite from the Lake Baikal in Russia. Wyoming jade is the trade name for nephrite from Wyoming (USA). Jadeite is much rarer than nephrite and therefore regarded as more precious. The most valuable jade is called imperial jade. In both minerals, the way the color is distributed varies a great deal. Only in the very finest jade is the color evenly distributed. In the West, emerald green, spinach green and apple green are regarded as particularly valuable. In the Far East, on the other hand, pure white or a fine yellow with a delicate pink undertone is highly esteemed. Jade looks best in daylight. In both minerals, the way the color is distributed varies a great deal. Only in the very finest jade is the color evenly distributed. Both, nephrite and jadeite often have veins, blemishes and streaks running through them, though these may not always be regarded as flaws. On the contrary, some of these patterns are considered particularly valuable. Since jade is, as a rule, not transparent, but has a fine luster, the cabochon is the form best suited to it. Thin slivers, which can be worn as pendants, and jade bracelets are popular too. Round, cylindrical and flat shapes can be combined to make attractive necklaces. Traditionally, jade is also carved into slender figures, filigree images or thin-walled vessels.

The most important deposits of jadeite are found in upper Myanmar (Burma). Other locations are in Canada, China, Guatemala, Japan, Kazakhstan, New Zealand and Russia. Deposits of nephrite are found in Alaska, Australia, Brazil, Canada, China, Russia and Taiwan.

Occasional dying and wax or plastic-type resins impregnation, to improve color and appearance are used.

During the 1870's, the jade-fever caught collectors in the West, including such distinguished personalities as J.P. Morgan and Alfred Nobel. Later the rich and the famous became obsessed by the stone and the most prominent collector was Woolworth heiress Barbara Hutton.

The spell of jade is unbroken and continues to generate headline news. Christie's in Hong Kong for instance sold in November 1999 a jade bracelet for about US$ 2.5 million, a record for the size and quality of jade. A 77.1 carat jade cabochon ring was sold for US$ 2.4 million.

Jade Gemology
Species: Jadeite/Nephrite
Color: Green, also other colors
Chemical composition: NaAlSi2O6 sodium aluminum silicate/ Ca2(Mg,Fe)5(Si4O11)2(OH)2 basic calcium magnesium iron silicate
Crystal system: Monoclinic, intergrown, grainy aggregate/ fine fibrous aggregate
Hardness: 6.5 - 7 (Mohs scale)
Specific gravity: 3.30 - 3.38/ 2.90 - 3.03
Refractive index: 1.652 - 1.688/ 1.600 - 1.627
Birefringence: 0.020/ -0.027, often none
Absorption spectrum: Green jade: 691, 655, 630, 495, 450, 437, 433/ 689, 509, 490, 460
Fluorescence: Greenish jade: very weak; whitish glimmer/ None

In the pre-Columbian period, the Mayas, Aztecs and Olmecs of Central America honored and esteemed jade more highly than gold. New Zealand's Maoris began carving weapons and cult instruments from native jade in early times, a tradition which has continued to the present day. In ancient Egypt, jade was admired as the stone of love, inner peace, harmony and balance. As early as 3000 B.C. jade was known in China as "yu", the "royal gem". In the long history of the art and culture of the Chinese empire, jade has always had a very special significance, comparable with that of gold and diamonds in the West. Jade was used not only for the finest objects and cult figures, but also in grave furnishings for high-ranking members of the imperial family. Today, too, this gem is regarded as a symbol of the good, the beautiful and the precious. It embodies the Confucian virtues of wisdom, justice, compassion, modesty and courage, yet it also symbolizes the female-erotic.

In Antiquity, as well as in the Middle Ages people believed that the cosmos is reflected in gemstones. Jade is assigned to the planets Jupiter and Pluto.

The healing powers of gems remain a controversial issue, but are mentioned for centuries by healers, shamans and medicine men. Whether it's a fact or a placebo effect doesn't matter if it helps. The safest approach is to wear the gemstone in skin contact to the troubled part of the body. Jade is said ever since to be of help for kidney diseases.