INFORMATION ABOUT JADE AND NEPHRITE AS USED IN ESTATE JEWELRY
Jadeite and nephrite are the most durable stones and both are very resistant to breaking or chipping. Neither are easily broken with the blow of a hammer. Jade may be formed into fine and intricate designs without breaking. Both jadeite and nephrite accept a fine polish because of their compactness. Jadeite and nephrite come in a variety of similar colors and patterns.
BIRTHDAYS AND ANNIVERSARIES
Jade is recognized as the 12th anniversary stone.
ORIGIN OF NAME
The name for jade is actually a misnomer. The Spanish conquistadors were said to have given jade its name "piedra de yjada" or "stone of the loins". The conquistadors saw that the Mexican natives were wearing the green stone to relieve kidney ailments such as nephritis (kidney inflammation) and called the stone jade the Latin name "lapis nephriticus" or "stone of nephrite". When the stone was brought back to Europe, it was mistranslated from Spanish to French as "pierre de jade". Later the Latin term was reduced to "nephrite" and was used as an alternate word for jade. In 1863, the French chemist, Augustine Damour, chemically analyzed a Burmese stone and realized that jade was two different minerals, so the term jadeite was used for Burmese jade to distinguish it from Nephrite or Chinese jade. Chinese had distinguished between the two jades from the mid - 1700's. Nevertheless, the common term "jade" continues to be used for jadeite and nephrite. In ancient cultures similar stones have also been labeled "jade".
Jadeite and nephrite have both been used to make tools from primitive times. Jade was most likely used in China longer than anywhere else, nephrite being the most often used. According to Chinese folklore, jade weapons and jade tablets were used in battle in the twenty-seventh century B.C. Jade has played an important role in almost every part of Chinese life. The Chinese have used jade as tools, currency, incense burners, marriage bowls, round buttons used for fingering, gifts for visiting leaders and awards for war heroes. The earliest preserved records are inscribed nephrite tablets. Musical instruments have also been carved out of jade by the Chinese. Jadeite was also valued by the Mayans and Aztecs. In Mexican artifacts, jade is found to be carved into jaguars and choppers for ceremonial purposes. The Spanish conquistadors destroyed the art of jade carving in the Americas.
ESTATE JEWELRY AND ANTIQUE JEWELRY USING JADE
Jade was a popular stone used found in jewelry from the Art Nouveau Period and the Art Deco Period. Jade continues to be popular in current jewelry and contemporary vintage jewelry.
Chinese have always admired nephrite more than other gemstone. From Neolithic times, they have carved flat discs with a centered hole called pi, used to worship heaven. In a 1596 Chinese encyclopedia, a drink of jade, rice and water would strengthen muscles, harden bones, calm the mind and purify the blood. Jade was also believed to be important to Chinese after their death. A burial shroud was made of jade sewn together with gold for princess Tou Wan in the second century B.C. Carved amulets were put in the deceased's mouth and favorite pieces were put on different parts of the body and clothing. These jade stones were believed to prevent the body from decaying. In pre-Columbian Mexico and Central America, jade held a talismanic power. Jade was put in the mouth of a dead nobleman to serve as a heart in the afterlife. Jade was ground and mixed with herbs to be used as treatment for fractured bones, fevers and to revive the dying. In New Zealand, the Maoris also considered jade to be an important talisman. They used jade to make hei-tiki pendants, the gross human faces or forms that were passed down to the male heirs from generation to generation.
Jadeite and nephrite are both aggregates (rocks). They are both masses of interlocking crystals, rather, than single crystals like most gemstones. Jadeite and nephrite have different compositions and properties.
Jadeite rock is very rare because its formation also requires conditions of considerable depth of burial that are infrequently preserved geologically. The durability of jadeite and nephrite are results in their survival as stream cobbles and boulders.
Myanmar is the major producer of jadeite and the only significant source of imperial jade. It is most likely the oldest source. Prehistoric jadeite instruments have been found in the Mogok region. Jadeite is also produced commercially in Guatemala, the Soviet Union, the US and Japan.
The oldest source is known to be Eastern Turkistan. Nephrite has also been found in Russia, Taiwan, Poland, Germany, India, Zimbabwe, Australia, Mexico and New Zealand. British Columbia, Canada is the largest supplier of grayish, green nephrite. Alaska, California and Wyoming are also sources of nephrite.
ESTATE JEWELRY CARE INSTRUCTIONS FOR JADE
Ultrasonics are not advised for treated stones. Ultrasonics and steamers are generally safe for untreated stones. Avoid chemicals, acids and high heat.
The differences in quality and prices vary greatly in jade. Color and translucency are the major areas to consider when evaluating both jadeite and nephrite. The rarest and most valued jadeite is pure, even and intense emerald green. When emerald green jadeite is combined with maximum translucency and smooth texture the imperial jade stone will command a high price. Jade commands high prices when the color is pure, intense and uniform even if it is opaque. Jadeite commands higher prices than nephrite in gemstones. Other considerations need to be made for carvings, such as design, craftsmanship and antiquity. Jadeite is more valuable and rare than nephrite. Nephrite is more plentiful and most of it is grayish green - typically forest green or olive green.
VARITIES AND COLORS OF JADEITE AND NEPHRITE:
EMERALD GREEN JADEITE: This is the most expensive jade. To be called imperial jade it must also have the finest translucent quality. It has chromium to help make its fine green color.
LEAFY AND BLUE GREEN: has iron in its properties.
LAVENDER JADEITE: this can range from light grayish-pink to a deep purple. Has manganese and iron as properties.
WHITE JADEITE: usually ranges from translucent gray-white to an opaque, milky white. This is considered to be pure jadeite.
DEEP GREEN NEPHRITE: very abundant and affordable. The antique value of jewelry is often more significant than the actual value of green nephrite. Has blotches caused by graphite inclusions.
WHITE NEPHRITE: usually a grayish white color. It is sometimes called "mutton-fat" jade when it has a yellowish tint. White nephrite is used to make carvings. Essentially it is pure tremolite with very little iron.
CREAMY BROWN NEPHRITE: sometimes the stone is called tomb jade, once attributed to the action of heat on lime impurities but research indicates it is the result of reactions between fluids in mummies and jade, both sealed in sarcophagi.
RED JADE: usually comes in orange, brown or rust colored. Jade found in tombs can also look reddish-brown on the surface and along cracks. This color is caused by the oxidation of the iron content from surrounding water or earth.
BLACK OR GRAY JADE: Black jade is mined in Wyoming and Australia, normally is nephrite. Black and gray jade have just recently been used to make jewelry.
JADEITE TECHNICAL DATA
Crystal system: monoclinic
Refractive Index 1.66 - 1.68
Optic: AGG double refracting and biaxial positive
Specific Gravity: 3.30 - 3.36
Hardness: 6.5 - 7
NEPHRITE TECHNICAL DATA
Crystal system: monoclinic
Refractive Index 1.60 - 1.63
Optic: AGG double refracting and biaxial positive
Specific Gravity: 2.90 - 3.05
Toughness: exceptional, tougher than jadeite
Hardness: 6 - 6.5
With a hardness of 6 to 6.5 for nephrite and 6.5 to 7 for jadeite, on the Mohs' Scale, nephrite and jadeite are fairly hard stones. Jadeite is an exceptionally tough stone and nephrite is an even tougher stone than jadeite. Valuable jade carvings have survived earthquakes and falls, when other hard objects have not survived. Nephrite is stronger because of its interferon, fiber like crystal components. Jadeite consists of crystals that are more granular and coarser. These components are sometimes visible without a loupe or other magnification.