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OPAL - More to the story
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| Oooh, Aaahhh, Ohhh! OPAL (OH –puhl) Information about one of nature’s most unusual and unique gems. Near Coober Pedy, Australia  Photo found on Flickr taken by Georgie Sharp | ....................................................... Do you have an opal find that you would like to share? Contact me and I will post a photo of your treasure here. ....................................................... | |||
| What is Opal? Opal is a mineraloid gel which is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, and basalt. | ||||
| Chemical formula Hydrated silica. SiO2·nH2O | ||||
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| Virgin Valley (Nevada) Opal has long been acknowledged as some of the most beautiful opal in the world. Most Virgin Valley opal cannot be cut because it easily fractures or crazes when placed against the cutting wheel. By using a long term stabilizing process some of this opal can successfully be cut into finished stones that are valued as precious opal. Bonanza Opal Mines in located in Denio, Nevada is where The Travel Channel's show Cash and Treasures visited to search for Opals in their first season. | ||||
| Spencer opal is mined in Spencer, Idaho. Most of it is used to make doublets[f] or triplets[f]. On rare occasion some is mined that is thick enough to cut a solid stone and classified as precious opal. The doublets and triplets are usually very brilliant and beautiful but since they are not solids they would be classified as noble opal. Spencer Opal Mine offers digging your own opals for a fee. Honduras opal: At one time this opal was in demand but at the present time the opal mined in this area has to be treated to enhance its' appearance. For this reason it has lost favor with most knowledgeable buyers. Opals from Mezezo, Ethiopia, have been well-known for more than 10 years for their amazingly sparkling brown and hydrophane varieties. Other deposits (re)discovered more recently yield precious opals : white, fire, crystal and sometimes black ones, all of exceptional quality. [e] There are many types of opal some of which are described below. The way precious and common opal are differentiated are by the type of spheres that occur when water percolates through the earth and enters a cavity in the host where the silicates are deposited as tiny spheres. If they are uniform in size and shape, they will diffract light. If they are random in shape and arrangement, we have common opal. Types of Opal COMMON OPAL Common Opal is opal that does not contain gem colors. Common opal has the same chemical composition as gem opal; but where gem opal contains microscopic spheres arranged in a regular array, in common opal the arrangement of spheres is irregular. The best-known kind of common opal is potch, which may be black, grey, white or amber-colored. A natural backing or body of black potch is a defining characteristic of black opal (See 'Black opal' below). [b]  | ||||
| PRECIOUS OPAL Precious Opal is a valuable gem-variety of Opal. Precious Opals are identified by their unique play of color which can range from milky white with blue, green, red fleck (or any combination thereof), to intensely dark with flashes of red, orange, green, teal, yellow, blue, and violet. Opals with flashes of red are considered more valuable. [b]  [b]Photos by Stan Celestian Courtesy of Glendale Community College/ Maricopa County Community College District. | ||||
| CRYSTAL OPAL Crystal opal is any kind of opal which has a transparent or semi-transparent body tone - i.e. you can see through the stone. These stones are very translucent with glints and flashes of color when the stone is turned and rotated in the light. During the 1970’s there were many “antique-style” settings for these types of opals and are probably the most recognized opal in the United States. I guess those “antique-style” rings will be genuine antiques in a very short time. | ||||
| ETHIOPIAN OPAL (CONTRA LUZ OPAL) Ethiopian Opals are similar in characteristics to crystal opals but have the ability to create color flash as light passes through from the opposite side. [d]  | ||||
| FIRE OPAL Fire opal is a term not commonly used within Australia but is quite common in North America. Technically, Fire Opal is closely associated with, but not exclusive to the opal mined in Mexico, which usually has a distinct orange coloring, however as pictured in the next description, there have been opals located in Oregon that are also classified as fire opals. Fire Opals are transparent to semi-transparent with a strong base color from water-clear through distinct transparent bluish, and covering the color spectrum from pale yellow, through orange to reddish brown. These opals have no play of color and if they do, they are then classified as precious opal. [e]  | ||||
| OREGON OPAL During 1988, West Coast Gemstones, Inc., began mining and marketing a variety of very fine-quality opals from Opal Butte in Morrow County, OR. Exquisite stones as large as 315 carats have been cut from contra luz rough from this deposit. West Coast has developed methods of drying the opal that greatly reduce crazing. Even with the drying procedures, the stability varies from 20% to 90% depending upon the variety. The opals are found in rhyolite geodes (thundereggs) in a perlite that has altered to a pastel colored clay. The geodes that contain gem-quality opal are only about 10% of the total geodes mined and only about 1% of the geodes contain gem-quality opal with play of color. The remaining geodes contain agate, quartz crystals, or common opal. The geodes vary greatly in size, from a few centimeters in diameter to over a meter. | ||||
| Photo found on Flickr by adamantine of a 3 cm piece of fire opal from Opal Butte, Oregon. | ||||
| BLACK OPAL Black Opals are usually mined in Lightning Ridge, New South Wales, and are the most famous, and sought-after type of opal. The term 'black opal' does not mean that the stone is completely black (a common mistake), it simply means the stone has a dark body tone in comparison to a white opal. [g]  [h] [i]  [n]  BOULDER OPAL Boulder opal forms in Queensland on ironstone boulders. This type of opal is often cut with the ironstone left on the back creating a natural doublet. The opal seam is usually quite thin so leaving the ironstone on the back allows the opal to be be very dark and beautiful in color. Boulders vary in shape and size, from as small as a pencil eraser, to as big as a small watercraft (I want one of these!). Boulder Opal has a tendency to cleave; when cleaved the "split" leaves two faces of opal, with a naturally polished face. [g]  [g] | ||||
| BOULDER OPAL MATRIX Natural boulder opal matrix is another kind of matrix opal, found at Yowah in Queensland, which in its natural state consists of brown ironstone with small deposits of opal interspersed. This kind of opal is not treated. [g]  [n]  | ||||
| YOWAH NUT OPAL Found in South Western mines at Yowah in Queensland, Yowah nuts are ironstone concretions resembling 'nuts' which contain precious opal in their center. | ||||
| Click the link to see close up and view the amazing colors VERY LARGE FILE BUT WORTH IT | ||||
| MATRIX OPAL Matrix opal is where the opal occurs as a network of veins or infilling of voids or between grains of the host rock (ferruginous sandstone or ironstone). Matrix comprises precious opaline silica as an infilling of pore spaces in silty claystone or ironstone. It generally shows fine pinfire colour in the natural state. Boulder 'matrix' opal is a peculiar formation where flecks of rich, flashing colours of opal are scattered throughout the brown ironstone, like twinkling neon lights of a distant city.  | ||||
| ANDAMOOKA MATRIX OPAL (TREATED OPAL) Andamooka Matrix Opal is treated Limestone. To find out more about this mysterious way to create beautiful Matrix opals, visit The Shed . [i]   [i] | ||||
| Is it Really Opal? Sometimes you can be just as amazed by some beautiful treasures or fossils that are opal like or have opalescent qualities. Found primarily along the eastern slopes of the Rocky Mountains of the United States and Canada, Ammolite is a rare and valuable opal-like organic gemstone. Ammolite is also known as aapoak (Kainah for "small, crawling stone"), gem ammonite, calcentine, and korite. The latter is a trade name given to the gemstone by the Alberta-based mining company Korite International, the first and largest commercial producer of ammolite.[a] Ammonites lived in prehistoric waters next to the Rocky Mountains and became extinct 65 million years ago. The largest deposits of gem-quality ammonites are located near Alberta and Saskatchewan,  Canada, and south to Montana in the United States. Most of the deposits are located on the eastern slopes of the Rocky Mountains. [d] According to Wikipedia, the internet's free encyclopedia, "Ammolite is made of the fossilized shells of ammonites, which are composed primarily of aragonite, which is the same mineral that makes up nacreous pearls. The thicker the layers of aragonite, the more red and green are produced. Thinner layers of aragonite yield blue and violet colors. Red and green are the most commonly seen. Ammolite is one of three biogenic gemstones, the other two being amber and pearl. In 1981, ammolite was given official gemstone status by The World Jewelry Confederation and by CIBJO (International Commission of Colored Gemstones). It is considered the rarest organic gem material." (Source for paragraph above: Excerpt from www.sparklingsplendor.com ) Visit the site for additional information and beautiful jewelry made from these specimens. More specific information on Ammolite with additional details and photos may be found here: | ||||
| SYNTHETIC OPAL Sometimes referred to as Gilson opal, a lab-created synthetic opal, has a similar structure to that of precious opal. Synthetic stones show extremely bright colors, and larger color patches than a natural opal. Synthetic material shows a more structured array of colors because the intricate pattern of natural opal cannot be duplicated.[o] [l]  You will also come across imitation opal which has been created by placement of colored tinsel or glass placed beneath a crystal topper and constructed similar to that of an opal triplet. With practice and a good eye you will soon be able to differentiate between earth’s natural opals and the man made variety. [m]  _________ I hope this information has been somewhat informative and helpful. The above content compiled by member ‘dancingflowers’. Acknowledgements to the following: [a] Wikipedia, [b]Stan Celestian & Graham County Community College, [c] Betty’s Opals, [d] Oplainda, [e] Gemstones and Rough , [f] International Gem Society, [g] dancingflowers collection , [h] iOpal , [i] Shed.com, [j] Opals Down Under, [k] Sparkling Splendor, [l] Profound Glass, [m] Alibaba [n] OpalMine.com, [o] Costellos For additional information on these fabulous gems vist our Cash and Treasures Member, Petren and make a visit to his blog which he has contributed as a link on his profile. Petren is the EXPERT, I'm just an opal lover! Please report broken links to dancingflowers |
dancingflowers |
Latest page update: made by dancingflowers
, Aug 27 2009, 12:10 PM EDT
(about this update
About This Update
making fit to page on main table for sizing,
- dancingflowers
view changes - complete history) |
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Keyword tags:
Arizona
Australia
Black Opal
Canada
Common Opal
Fire Opal
Nevada
Opal
Oregon
Precious Opal
More Info: links to this page
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| Started By | Thread Subject | Replies | Last Post | ||
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| DiamondProspector | Wyoming Giant Opal field | 13 | Feb 7 2009, 2:54 PM EST by aubreyreynolds9@gmai | ||
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Thread started: Feb 3 2009, 12:09 PM EST
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Wow, these a beautiful photos. When I finally figure out how to use this website, I'll add photos and maps. I collected hundreds of thosands of carats in a perviously unknown giant opal field south of Riverton Wyoming. It mostly consists of common opal (and I kid you not, when I first went into this field, one could pick up dump truck loads in 30 minutes without any effort), with some spectacular Sweetwater agate, one hill of solid fire opal, and minor amonts of precious opal in veins. The depsoit is mostly unexplored and is found in parts of 14+ square miles.
I wrote about this in the ICMJ Prospecting and Mining Journal - (2008, Cedar Rim Opal - Discovery of a Giant Opal Field: ICMJs Prospecting & Mining Journal, v. 78, no. 2, p. 18-45) and have information on my websites at http://danhauselauthor.pbwiki.com/Discoveries and http://geologicalconsulting.pbwiki.com/Opals and at http://kimberlite.pbwiki.com/DISCOVERIES |
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| pvjjh | Opal Page | 3 | Feb 1 2009, 2:17 PM EST by syonix | ||
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Thread started: Jan 30 2009, 12:38 AM EST
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This looks great! WOW it is some beautiful material. Just need more money to go play moe! lol
The only suggestion I may have is to size the picture down bit.. I think that will shrink the discription - verbage a little. Maybe it is just my screen, but I had to scoll accross the page to read the full description. The right side was just slightly off my screen. But I think it looks great and reads very well. Paul
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Keyword tags:
Arizona
Australia
Black Opal
Canada
Common Opal
Fire Opal
Nevada
Opal
Precious Opal
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