Mineral toughness is rarely considered in mineralogy books, but any discussion of jade always leads to a discussion of toughness. The toughness of a mineral is represented by its fracture strength or ability to resist fracturing, which is about 30, psi for nephrite. In other words, it takes a lot of pressure to fracture a coherent piece of jade. Only carbonado, a black granular to compact industrial form of diamond, is tougher than jade; whereas gem-quality diamond is hard, but not all that tough.
Gem diamond can scratch almost anything, but it can be smashed with a little effort with a blow from a hammer. It is the toughness of jade, combined with hardness that makes the gem carvable, durable and unique. Look closely at this jade and you will see several individal jade crystals that are roughly hexagonal. These are also jade pseudomorphs after quartz. During the geological past, the jade slowly replaced the quartz one atom at a time without disturbing the original crystal habit of the quartz W.
Dan Hausel, collection. Jade ranges from opaque to translucent masses and has a vitreous to waxy luster and is reported in a variety of colors including black, white, and several shades of green. The green color is due to the presence of iron. The greater commercial values are attached to the lighter green translucent varieties. Rare emerald green jade is colored by iron and trace amounts of chromium. The extraordinary color of apple green jade from Wyoming.
The origin of nephrite jade was investigated in the s. It is thought that nephrite formed by metasomatic alteration of amphibole during metamorphism. This means that hot fluids reacted with existing amphiboles and slowly replaced them by extracting some atoms and replacing those atoms with new atoms. In Wyoming, this happened when these rocks were buried under several miles of rock about 2 to 3 billion years ago.
Blocks of amphibolite were disrupted and trapped in a molten granitic rock and portions of the amphibolite xenoliths were altered to jade by the hot granitic fluids. These reactive fluids not only produced jade, but they also altered the surrounding rocks to produce a group of minerals that included clinozoisite, zoisite, sericite and chlorite.
When found in outcrop, nephrite jade is associated with this distinct assemblage of minerals that form an alteration halo around jade. This halo consists of bleached leucocratic white granite-gneiss that is mottled pink and white, some secondary greenish clinozoisite, pink zoisite, pistachio green epidote, green chlorite and fine white mica. This alteration halo can be used as a guide to find hidden jade deposits. While exploring between some jade deposits north of Jeffrey City to the jasper deposits in the Tin Cup district to the west, I found more than a dozen such halos — a couple had exposed jade, others did not.
The ones without jade, such as shown in the photo below, likely have hidden jade at shallow depth. Wallrock alteration found with jade includes bleached white granite gneiss with pink zoisite, green chlorite and trace epidote. While searching north of Jeffrey City, I found more than a dozen areas with this characteristic alteration halo.
Where found, this halo represents places where jade or hidden jade is likely to be found with some digging. Leaf-green jade fashioned into arrowheads.
The name jade comes from the time of the Spanish conquest of Central and South America where jade and jade carvings were prized as much as gold by the Aztecs. The Spanish used the name piedra de hijada, or stone of the side, because it was believed that jade cured kidney ailments when applied to the side of the body.
The Spanish also called this stone kidney stone or piedros de los rinones, which translated into Latin as lapis nephriticus. The term nephrite anglicized the Latin term for jade.
Although primary deposits of jade are important, much of the finest material comes from secondary alluvial deposits. Some incredible pieces of jade have found their way to the jewelry industry.
In , a 2-inch diameter 0. All of the jade found in Wyoming is nephrite, whereas much of the jade mined in the Orient is jadeite. For those interested in searching for jade in Wyoming, it is found primarily in the Granite Mountains and to the south at Crooks Gap-Green Mountain. It has been reported elsewhere in the state, but much of the material reported outside of the Granite Mountains has turned out to be serpentinite.
Cobbles and boulders are found south of US Highway while jade in place is found in outcrops to the north of the highway in the Granite Mountains. The jade localities are described in the following books:.
Hausel, W. Booksurge, p. Many were prospected in the past and thus most are now marked by old prospect pits. Look on Google Earth for prospect pits and then visit them. But much of the high-quality easily found, emerald-green and translucent jade was found in Tertiary conglomerates at Crooks Gap. Lower quality light-g reen jade was found in place to the north of Crooks Gap in the Granite Mountains, but the source of the valuable emerald green was never identified and remains to be found.
In the s and s, many jade boulders weighing several hundred pounds were found near Jeffry City in central Wyoming. Jadeite has never been found in Wyoming. It forms at high-pressure and low-temperature from near surface to depths as great as 30 miles.
Geologically, it is found near convergent continental margins where there is considerable pressures and temperatures from tectonic stress , and forms by fluid interaction with serpentinizing peridotite at depth.
Only three count ries produce jadeite on a commercial scale: Burma, Guatemala and Russia. The jadeite from Guatemala is granular, mottled, and opaque. Burmese jadeite has more intensely saturated colors of deep-lavender to emerald- imperial green. Jadeite from Russia, although generally dark-colored, tends to sit between the Burmese and Guatemalan jadeite.
Jadeite has not been identified in Wyoming. Nephrite jade is produced primarily by Canada. Wyoming produced large quantities of fine nephrite in the past, but there is no longer commercial production.
Russian nephrite was exported to China in the past and most Russian jadeite was sold through markets in Hong Kong as Burmese jadeite. In Eastern Turkistan, the jade market is strictly controlled by the Chinese government and only government buyers can purchase jade at the price set by the government.
Can you guess which of the two minerals above is jade? And with a little effort, it can also be scratched with a pocketknife, unlike the real jade nephrite to the left. Intrigued by all of the treasures out there in the world to be found? There are geological hints on where and how to find jade and hundreds of other mineral deposits. Wow, can you believe this specimen?
In this case you will find that it cannot easily be isolated from the other rocks. The first test that should be done is to establish the amount of iron in it, if the iron elements are found to be of high levels and its dark black, the probability of having jade is high. Black colored jade contain high levels of iron. True Wyoming jade when scratched will not respond to the scratch, the process will appear slippery and on the point of scratch, it might appear white, this is the pilings of the blunt material that was used to perform the test.
When it held in the hand, the holder will feel cold and the condition will take time for the jade to fluctuate with your body temperature. Jade can sometimes show the point of separation if they underwent or developed schistosity.
Some of the valuable gemstone that have been proven to exist in the state are; opal, sapphire, diamonds, agate, quartz crystal and petrified wood. This is a very diverse state from a geological perspective, and it has a lower population than any other state in the USA, which means the likelihood of undiscovered mineral deposits is quite high. Rare Gold Nuggets. September 9, Recent Posts , Rockhounding. Search This Site by State or Topic :.
Gold Mining Around the World! Most Popular Pages:. About Us. Geologists collected some 62 samples of various jade types, colors and textures as well as their associated host rocks, which are currently being evaluated to confirm mineralogy, texture, translucency and general workability as ornamental, carving or gem material. As the Company will advance these newly acquired Wyoming properties through continued laboratory testing, analysis and field exploration work.
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