Hundreds of minerals and precious gems are formed by the earth. One of the hundreds is jade. Jade is one of the most interesting minerals because of its long history. Throughout past centuries jade has been
revered for its alleged healing powers, strength for tools and weaponry, and praised for its beautiful carvings in art. This paper will discuss the unique properties and characteristics of jade, the formation of jade, its special history, and the issues with synthetic jade and how to identify the real, truly beautiful mineral.
There are two different minerals that can be identified as what most of the population would call jade, nephrite and jadeite. Although they appear to be the same they each have their own unique properties and characteristics. Nephrite is a chemical mixture of actinolite and tremolite and is calcium and magnesium iron silicate occurring in colors ranging from white to spinach green to black. Nephrite is part of the group of rock forming minerals called amphiboles (Desautels 1960). It is a double chain silicate and also contains water (Keller 1990). Jadeite is sodium aluminum silicate often found with calcium and iron and occurs in colors ranging from white to emerald green and other colors. Jadeite is part of the rock forming mineral pyroxene group (Desautels 1960). Like nephrite, jadeite has small crystals that interlock which give it its durability and strength; however it doesn’t have the double chain like nephrite because it is not an amphibole. For the purpose and requirements of this paper, the focus will be on jadeite. In addition to its unique chemical makeup of NaAlSi2O6 (Holden 1991), jadeite has several other interesting properties and characteristics as well. The color of jadeite can vary from white to green, white with greenish spots, pale lavender, bluish lavender, emerald green (known as “Imperial Jade”), silvery white, reddish brown, and brownish red (National Audubon Society 1998) and its luster can be described as a dull or waxy appearance (Holden 1991). Jadeite has a hardness of 6 ½ – 7 on Mohl’s scale (National Audubon Society 1998). Jadeite cleavages in two directions at almost 90 degrees (87 degrees and 93 degrees), which makes it very distinct (National Audubon Society 1998). It has a specific gravity of 3.3 to 3.5 (National Audubon Society 1998) and a monoclinic crystal system (Holden 1991). Jadeite is very brittle and tough and can be transparent to opaque (National Audubon Society 1998).
Jadeite’s unique characteristics and properties are largely due to the way in which jadeite is formed. Jadeite is formed by “high-pressure regional metamorphism, which occurs where rocks are subjected to very deep burial but relatively low temperature” (Keller 1990). The process of high-pressure and low temperature conditions occur beneath the surface of the ocean and over millions of years. Peter C. Keller Ph. D. states that when the ocean floor slides beneath the edge of a continent the high-pressure and low-temperature conditions occur that are necessary for jadeite to occur (Keller 1990). This happens because the clashing of the two pieces of rock form a great amount of pressure yet the cold temperatures of the ocean result in the low-temperature needed for this mineral to come about. As pieces of the ocean floor fall off and are pushed back into the earth’s surface, recrystallization occurs with significant high-pressure (Keller 1990). The resulting rocks are known as blueschist or prehnite and vesuvianite in and jadeite is finally located in lode hydrothermal replacement deposits (National Audubon Society 1998). These special circumstances result in the mineral known as jadeite and the rocks, which are iron rich, affect the color of the jadeite that is formed. This is particularly special to jadeite because the color of jadeite is what can determine its market value. For example, “Imperial Jade” which is a deep, rich shade of green, is highly valued by art collectors and jewelry collectors alike. This highly valued shade of green occurs due to the presence of chromium (Hall 1994). Jadeite predominantly found in Burma, San Benito Co., California, and also Cloverdale Sonoma Co., California. Jadeite deposits have also been found in Guatemala, China, Japan, New Zealand, Western Canada, Alaska and even Wyoming (Holden 1991). One of the most important sources of jade is Myanmar, which has supplied China with jade for over 200 years (Hall 1994). Even though it seems that jadeite is found in many different places of the world, the gem quality of jadeite is actually very rare on a world-wide basis (Keller 1990).
Jadeite has a long and interesting history mainly due to its hardness and unique color. Early aborigines along the Amazon River used jadeite for tools and weapons because of its strength and hardness (Desautels 1960). After that, Spanish conquerors of Mexico and were introduced to jadeite when then came to Central America. They believed that jade held special healing powers, especially for kidney ailments (Holden 1991). They named jade “piedra de ijada” which is Spanish for “stone of the flank” (Holden 1991). Many years after the Spaniards where introduced to the mystical stone, jadeite was identified in 1863 by French chemist Alexis Damour and the scientific name was coined by the original trade name there after (Holden 1991). The ancient Chinese worked jadeite as early as 1000 B.C. for tools and other such uses. However, jade carving finally became a revered art subsidized by Chinese Royalty during the Ching Dynasty (1644-1912) and reached its peak in relatively modern times (Desautels 1960). Now these jadeite carvings are prized possessions of many art collectors around the world. Jadeite carvings can be priceless pieces of art sought after by many art collectors and can come with a hefty price tag (Holden 1991). Today jadeite is used and fashioned into beads, earrings, bracelets, and cabochons for rings or broaches (National Audubon Society 1998).
Because of its unique formation and sometimes high costs, it’s no wonder that many people have tried to simulate jadeite. There are several different way in which jadeite is copied. Serpentine is a jade stimulant because of its convincing color and luster, but is easily detected because it isn’t as hard as jadeite. Other green silicates like californite, massive diopside, and massive green grossularite garnet are also used to simulate jadeite and are more difficult to detect because of their similar hardness to jadeite (Holden 1991). Because of this, scientists, geologists, gemologists and even jewelers have found several ways in which to separate true jadeite from other imposters. One way is to use a petrographic microscope or a refractometer can determine the refractive index (Desautels 1960) which is specific to jadeite. The best method to precisely identify jadeite involved the X-ray diffraction powder method. This is the best method because it depends on the fact that every crystalline mineral yields a characteristic pattern stemming from difference in internal structure (Desautels 1960) and therefore isn’t confused with other minerals like those the appear to look like jadeite. Even though jadeite is a naturally beautiful mineral, there are ways that it is enhanced and altered to improve in physical appearance. Grey or pale green jadeite can be dyed to look like a strong rich colored jade, like Imperial Jade which is the most sought after (Desautels 1960). Other stones, like Quarzite, can be dyed to resemble or substitute jadeite (Desautels 1960). Jadeite is sometimes imitated with semi opaque or opaque glass. There are many ways in which jadeite can be faked or changed to be more appealing to consumers.
Jadeite is a special mineral that has been enjoyed by thousands of people in hundreds of different cultures and is still prized today by many. It is truly a beautiful mineral that has had many uses and meanings, each special to the individual. Jadeite will continue to be valued and treasured across the world.
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