Mined Precious
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US $14.00
 1066 ct Precious Natural Emerald Cabochon Earth Mined Emerald Gemstone US $6.53 |
 1245 ct Precious Natural Emerald Cabochon Earth Mined Emerald Gemstone US $45.48 |
Opal is the most colorful of all gems. Opal is frequently referred to as the "Queen of Gems". More than any other gem, each opal is distinctly an individual. Opal is an extremely rare gemstone and for this reason is precious. Precious opal, as compared to common opal, offers the rainbow iridescence that has been so highly prized since Roman times.
It is a fascinating gemstone with an ancient history. The name is believed to have been derived from the Sanskrit name "upala", precious stone. During the Medieval period, a change in color intensity of an Opal was believed to indicate ill or good health.
In India, the Opal is regarded as a lucky gemstone for those in business. The opal is said to help its wearer find true love. Did you know that opal is the birthstone for October?
It is a common fallacy that wearing Opal if it is not your gemstone will bring bad luck to the wearer. Perhaps one of the most common myths about opal jewelry is that it must soaked in water or it loses its luster.
Opal is considered a mineraloid because this structure is not truly crystalline. Opal is one of the few gemstones that are sedimentary in origin. White opal is an opaque stone in which the colors appear as flashes or speckles. In startling contrast to white opal is the black opal of Australia and Nevada. Opal is most often found in cracks, cavities, and in veins within rock. Opal is neither very hard (5 1/2 to 6 1/2 on a scale of 10) nor very tough. Opal is a delicate mineral, hydrated silica or amorphous quartz. Actually because opal is a gel, it is, strictly speaking, not a form of quartz. Precious opal is composed of small spheres of amorphous silica packed in a regular array. Opal is formed by silica when it is liquefied and then hardened. The opal is composed of particles closely packed in spherical arrangements. The opal is a formation of non-crystalline silica gel. Opal is hydrated silica gel, hardened and containing 5% to 10% water. Therefore, in the strictest sense, opal is a mineral until discredited. Opal is brittle, heat sensitive, and breaks and scratches easily.
Opal is the only gemstone that holds all colors of the spectrum. . The phenomenon displayed by opal is called play of color. Fire Opal is Opal with a red to orange color, and even yellow. Harlequin opal is one of the rarest. Black opal is generally more sought after and more valuable than light opal. Black crystal opal is a very clear opal, with many different colors flashing through it. Like the popular black opal stone, the boulder opal is dark in tone. Precious opal usually only refers to solid opals, but Queensland boulder opal is often thick enough and of high enough quality to qualify. Not all opal is so precious however. Common opal is mostly opaque and shows no play of colors. Common opal is rarely transparent, but may be colored or contain inclusions.
Opal is one of the few minerals, which can be extracted economically by a miner working alone. Australia supplies over 98% of the world's Opal and the most valuable, the Black Opal, is mined at Lightning Ridge. The first mining claim was pegged on 9th February 1915 and in 1956 the largest precious opal gem in the world named "Olympic Australis" was found.
Nevada is known for precious opal from Virgin Valley. Precious opal was first discovered in Virgin Valley, Nevada in 1905. Two commercial mining operations in Arizona produce blue precious opal. There are two geological occurrences of precious opal in Australia. The greater part of the world's supply of precious opal comes from the Coober Pedy and Andamooka fields in South Australia. There are three types of precious opal found in Australia: - the Boulder, the Light (or white) and the Black. All precious opal in South Australia occurs in rocks affected by weathering during the Tertiary Period, some 15 to 30 million years ago.
The doublet is a slice of precious opal glued onto a backing of non-precious opal called "potch". We call it potch and it is what is termed common opal. Common opal, is amorphous and rather opaque, and some of its varieties are named honey opal, milk opal, and moss opal.
Now that you know about Opal, find out where to buy it at Gems Explained [http://www.gemmex.org]
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Precious $10 Precious |
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Gold Nuggets Mined in Alaska $39.99 George F. Mobley Gold Nuggets Mined in Alaska - Photographic Print |
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Lines from a Mined Mind $14.95 Lines from a Mined Mind brings together lyrics and musings from the twenty-five-year recording career of John Trudell, an internationally acclaimed poet, musician, and leader of the American Indian Movement. More than a simple anthology, this collection goes deeper, revealing the incendiary intersection of music and activism. |
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The Recovery Potential of Mined Sites $108.33 This book takes a look at the self recovery potential of minedout forest sites in Guyanas forests. Only about 40 of the 1000 timber species are selectively logged for commercial use leaving the remaining forest relatively undisturbed. This undisturbed state is however threatened by conflicting land use in the form of mining which has resulted in many unresolved conflicts between miners and loggers. The book is based on a study which seeks to highlight the fact that if left undisturbed, mined out forest sites can recover through a process of natural regeneration. The study compares species in mined out sites with those in surrounding forests to detemine native species regeneration in the mine site, species type and richness and the influence of time and patch size on these. the study also seeks to give some insight as to whether minedout sites are capable of sustaining plant growth throughout the various stages of succession. Author: Bollers, Janice Binding Type: Paperback Number of Pages: 64 Publication Date: 2009/07/01 Language: English Dimensions: 9.00 x 6.00 x 0.15 inches |
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Gems, Crystals, and Precious Rocks (Hardcover) $43.74 Discusses the differences between rocks, minerals, and gems, their formation and composition, how they are mined, and how they are used. |
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Reclamation of Coal Mined Out Lands $109.93 Degradation of agricultural and nonagricultural land, decline in agricultural productivity, adverse effect on biodiversity, pollution of land and water are some of the visible environmental impacts/effects of coal mining. Derelict land, caused due to mining, and its management by reclamation techniques is a subject of both practical and ecological interest. The book provide a strategy to influence the course of land reclamation of coal mined out areas and conservation that has been developed through consultation and detailed study. The use of reclamation technologies may help in bringing back the normal ecology of the affected area. This book will be of interest to not only postgraduate students of applied environmental and agriculture sciences, but also intended for researchers, academician, and others actively involved in land reclamation and development projects. Author: Singh, A. K. Binding Type: Paperback Number of Pages: 76 Publication Date: 2011/07/17 Language: English Dimensions: 9.02 x 5.98 x 0.18 inches |
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Hoppers Hold Arctic Coal Mined Near Longyearbyen $39.99 Gordon Wiltsie Hoppers Hold Arctic Coal Mined Near Longyearbyen - Photographic Print |
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Interior of Big Bone Cave Once Mined for Saltpeter $39.99 Stephen Alvarez Interior of Big Bone Cave Once Mined for Saltpeter - Photographic Print |
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Boys Picking Slate out of Mined Coal in an American Mine $49.99 Boys Picking Slate out of Mined Coal in an American Mine - Giclee Print |
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Lines from a Mined Mind (Large Print 16pt) $29.89 John Trudells potent imagery and passionate convictions have established his international reputation as a poet and musician. Using his commanding voice, the peoples poet has also made great strides as a Native American activist, as a leader of the American Indian Movement, and as spokesperson for the All Tribes occupation of Alcatraz Island. For the first time, Lines from a Mined Mind brings together lyrics and musings from Trudells 20year recording career. More than a simple anthology, this collection goes deeper, revealing the incendiary intersection of music and activism. Author: Trudell, John Binding Type: Paperback Number of Pages: 298 Publication Date: 2010/05/07 Language: English Dimensions: 10.00 x 7.01 x 0.62 inches Large Print |
