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|One of the first faceted iolites from gemstones found in|
Wyoming by the author.
During the 1849er gold rush in California, more than 118 million ounces of gold were found by gold prospectors. Many of these discoveries began with prospectors simply using tin plates. When they found gold in their pans, they starting looking upslope for lodes filled with gold. Those who used diligent prospecting methods often found the source of the gold. In those days, panning had two purposes: to search for gold and to clean a dinner plate.
So did the 49ers find all of the gold? Nope, they only found the easy lodes. Remember, a lot of their gold came from placers and placers eroded from nearby lodes. It is likely the prospectors depleted many of the better placers, but they barely scratched the surface of the lodes! After searching for gold in Wyoming, it is apparent hundreds of gold deposits have been overlooked not only in Wyoming, but all over the US. We found gold all over southern Wyoming not only adjacent to Interstate-80, but even in the Laramie City landfill – all places no one had ever thought to look!
Today, the “Golden State”, home of the “Forty-niners”, divorced its heritage and chose bankruptcy over mining. Not a bright thing to do, but California’s politicians have never been accused of being smart. Not only that, California no longer allows people to use hobby dredges to dig for gold, even though the state was built on gold mining. Hobby dredges are essentially harmless, but Uncle Al and his followers find if anyone makes money besides them, then this is wrong.
|One of more than a hundred field trips led by the author to |
teach the public how to prospect for gold, diamonds and
And where did those diamonds come from? No one has yet found the source of the diamonds accidentally discovered by old gold miners. In the 19th century (as today) few prospectors had knowledge of what diamonds looked like, particularly since the great diamond rush in Kimberley South Africa, didn’t take place until 1871, twenty-two years after the great Californian gold rush. And it is likely thousands of diamonds were mined with the Californian gold and were rejected with quartz in the mine tailings, simply because the prospectors had no idea what the diamonds were. The diamonds from California ranged from less than a carat to one that weighed 32.99 carats (Hausel, 1998; Erlich and Hausel, 2002). It is important to keep diamonds in mind while prospecting for gold, because some are worth thousands of times more than an equivalent weight of gold (after faceting). And many collectors pay premium prices for raw natural diamonds from unique locations.
|While panning for gold, one often sees curious bystanders.|
In Wyoming, we recovered gold from many areas where gold had not been reported. But we also found gold right in the middle of areas where people had mined gold in historical past. In addition to precious metals, we found gem-quality garnet, chromian diopside, ruby and sapphire in streams, and a few placer diamonds were also found in streams by others. Some of these gemstones were even recovered from ant hills along with peridot gemstones. So there is still much to be found, even with a gold pan.
When I was a geologist working in Wyoming, I visited hobby dredgers in the Douglas Creek district in the Medicine Bow Mountains to see what they were finding in their black sands. While observing the dredgers, I noticed the trout played with their suction hoses as they kicked up sand, mud, and nutrients: if you want to see a school of fish, you will always find them around these hobby dredges. And it doesn’t take a genius to realize that when it rains, or during periodic flash floods, or during spring runoff from snow melt, Mother Nature dumps more dirt and mud into the creek than a million hobby dredgers could ever. Even so, prospectors are always blamed for environmental damage from naive regulators whether real or imagined. I found that nearly every regulator in Wyoming was either a member of an environmentalist group antipathetic to mining and the American way of life, or already had their minds made up. One of the worse bastions of radical environmentalists was in the forest service. Why are all of these people so dead set against others enjoying their lives and making a little money?
At one location on Douglas Creek, a prospector displayed gold in a pan. The gold was nice, but my eye was drawn to a small, rounded pyrope garnet. Diamond prospectors use pyrope as a guide to diamond deposits, since most erode from kimberlite pipes.
My field assistant and I had identified some cryptovolcanic structures upstream from this find on Douglas Creek and we wondered if these were unusual structures were the source of the pyrope garnets. Cryptovolcanic structures are circular structures with distinct vegetation anomalies similar to many known diamond deposits in the region.
Further upstream, a prospector had recovered two gem-quality diamonds with gold in a long-tom built in the side of Cortez Creek. The source of these diamonds has never been identified. At another location in the Medicine Bow Mountains in the Middle Fork of the Laramie River near the town of Centennial, people on one of my geology field trips recovered dozens of pyrope garnets in gold pans as they learned to pan: no gold – just a lot of diamond indicator minerals!
|One of many cryptovolcanic structures found in Colorado, Montana and|
Wyoming. This one (the depression) is actually a diamond-bearing
kimberlite pipe found in the Colorado-Wyoming State line district.
I never thought I would see the day, but there has been talk of banning gold panning in California. After years of panning for diamond indicator minerals in streams in search of diamond deposits, the only damage I can even imagine one might accomplish with a gold pan is develop stiff knees and lower back pains a trip to a chiropractor. Banning hobby dredging is bad enough, but is more like banning Tonka Toys to keep kids from digging holes in sand piles.
|Placer gold from Gerald Stout recovered on Rock Creek near |
Atlantic City in western Wyoming displayed in my space age plastic gold pan.
The lighter-colored material with lower specific gravity in your gold pan consists mostly of quartz, feldspar and mica. Quartz has a specific gravity of 2.6 to 2.7; feldspar 2.55 to 2.72 and mica 2.7 to 3. So these light-colored minerals should wash out of a pan fairly easily. Another white mineral that is periodically encountered is scheelite. It has a high specific gravity (5.9 to 6.1) and drives prospectors crazy who often think it is ‘heavy quartz’ that they cannot pan out without losing all of the black sands. So, if you have a lot of so-called heavy quartz, you might check to see if you are near any old tungsten mines – scheelite is a calcium tungstate and will glow light-blue under short wave ultraviolet light (Hausel, 2006, 2009).
When permeated with water, gravel and soil will tend to behave like a liquid. Stirring of the dirt in the pan with fingers will assist in sieving. To begin, fill the grizzly with gravel and place the entire pan under water working the fine-grained material through holes in the grizzly. Now take out the grizzly and examine pebbles on the sieve. If there is nothing of value, place this waste material in a pile on the stream bank (this will be a measure of how much you can pan in an hour or a day – you will likely be surprised at how little you can pan). The material sieved by the grizzly should be sitting on the fly screen in the pan. Work the very fine material through the fly screen.
|Some of the many hundreds of gemstones found in Wyoming |
If the black sands have no apparent gold, start a rhythmic slapping of one edge of the pan with one hand while holding the pan with the other while you still have a little water in the pan. If you have any gold, it will separate from black sand along the edge similar to what is known as a Wilfley Table.
With a 10-power geologists’ loupe, examine the gold. A common mineral mistaken for gold is mica. Mica has a low specific gravity (2.7 to 2.9). Even so, it is difficult to get out of your gold pan and will tend to stay in the pan because of its nearly two-dimensional crystal habit. It forms flat flakes that cut through water. Many prospectors have a tendency to let their imaginations run wild until they get use to seeing gold and mica. While panning, mica will tend to roll over and over in the water while gold will sit tight.
Pour the water out of the pan, wet your finger with saliva and touch any gold flakes or dust and place them in a tiny vial for safe keeping. Examine the gold either with the loupe or microscope. If you have pristine
Using your geologist’s loupe, look for tiny, equal-dimensional pink, red, orange and purple mineral grains in the black sands. These may be garnets. If they are clear and larger than about 4 millimeters, they could be facetable, particularly by specialized gem cutters in Sri Lanka and India. While searching for specific kinds of garnets in Wyoming, we found a few hundred anomalies that produced garnet and other gemstones which eroded from hidden diamond pipes somewhere upstream. The source of the garnets remains unidentified and suggests that someone, someday, might find many diamond treasures in the hills of Colorado and Wyoming.
Over the next few of years, I found a half-dozen ruby deposits, a giant iolite and kyanite deposit at Grizzly Creek, iolite at Ragged Top Mountain and also at Owen Creek in the Laramie Mountains and a deposit with millions of carats of kyanite. Some of the iolite at Grizzly Creek weighed many thousands of carats. One I carried in a backpack weighed more than 24,000 carats – the largest ever recorded. But much, much larger iolite gems were left in the outcrop!
The Orange River of southern Africa is well known for placer diamonds as are places in Brazil. In North America, there has only been a few placer diamonds reported outside of California. But based on the many diamond indicator minerals found in Colorado and Wyoming (as well as 120,000 diamonds mined from kimberlite rock) and the more than 100 kimberlite pipes in this region; it is surprising that more stream-deposited placer diamonds have not been found. The largest reported placer diamond from this region was 6.2 carats found in Fish Creek on the border of Colorado and Wyoming south of Laramie. The largest diamond found in a kimberlite
|Vein (lode) deposit seen in back (roof) of mine in California.|
Not long after the North Carolina discoveries, gold was found in Georgia. A gold rush in Dahlonega in 1829 resulted in as many as 500 gold placers and lode mines. Many nuggets were recovered including those of 54, 42, 40, 35, 26, 25, 19, 18, 15, 11, 6, 5, 4, 3 and 2 troy ounces. These were found in Gilmer, Habersham, White, Cherokee and Lumpkin Counties.
has been a good source for nuggets. The largest was discovered in 1998 in Swift
Creek near Ruby in central Alaska. The softball-size nugget, known as the
Centennial nugget, weighed 294.1 troy ounces. Another large nugget found on Long
Creek near Ruby weighed 46 ounces. Large nuggets were also found on Anvil Creek
near Nome in western Alaska that included nuggets of 182, 107, 97, 95 and 84
|Nuggets from the Kuskokwim Mountains in Alaska: |
the largest is about one troy ounce.
Another nugget, known as the Chicken Nugget, was found in Wade Creek near Chicken in eastern Alaska in 1983. This weighed 56.75 ounces. A nugget of 56 ounces was found on Dome Creek near Tolovana in central Alaska and a 52-ounce nugget was found on Lucky Gulch (Valdez Creek) near Denali in central Alaska.
Arizona has produced many gold nuggets, but these are small compared to Alaska and California. This is likely due to the lack of active streams although many are found in alluvium and fanglomerates along the sides of hills. A few of the better known places for nuggets in Arizona include the Potato Patch at Rich Hill in the Weaver Mountains and the Greaterville placers south of Tucson in the Santa Rita Mountains. Several nuggets were discovered in the Greaterville placers including one that weighed 37 ounces. Some of the nuggets in this district are reported to have had galena attached to the precious metal. Galena is a very soft, lead-sulfide mineral with perfect cleavage and will break down over a very short transportation distance. This along with angular blocks of rhyolite and granite in the placers supports that the Greaterville nuggets have a proximal source and likely eroded from nearby silver and galena-rich quartz veins.
In the Weaver Mountains, samples of quartz with visible gold are often found with nuggets. Gold in the nearby Bradshaw Mountains has been found in Lynx Creek, French Creek, Big Bug Creek, and the upper Hassayampa River. Based on the geology and location of gold nuggets found in Arizona, several gold deposits have likely been overlooked.
Large nuggets were mined in Montana at Alder Gulch and California Gulch near Phillipsburg in the southwestern portion of the state. In 1902, a football-size nugget of 612.5 troy ounces was recovered from California Gulch. This was followed by discovery of a 77 troy ounce nugget from the same gulch. The largest nugget found in Colorado weighed 160 troy ounces and was named Toms’ Baby found in 1887 on Farncomb Hill at the head of the French Gulch placer near Breckenridge.
The largest nuggets found in the US were from California. At Carson Hill in Calaveras County, a nugget weighing 2,340 troy ounces was recovered in 1854. Another water worn nugget of 648 troy ounces was found at Magalia, California in 1859. Both of these were too large to have transported any distance.
The largest nugget from Wyoming weighed 34 ounces. There was an very interesting reference to a boulder in Rock Creek at South Pass that contained an estimated 630 ounces of gold. If so, this nugget with attached quartz was likely the size of a football. Many nuggets were also recovered from Carissa Gulch.
So as you are looking for gold and other treasures with a gold pan, keep in mind how valuable gemstones can be. Gold is very valuable, but some pink and red diamonds have sold for as much as $1 million per carat. A carat is tiny compared to an ounce of gold and some of these diamonds have sold for many thousands of times the value of an equivalent weight in gold.
Erlich, E.I., and Hausel, W.D., 2002, Diamond Deposits – Origin, Exploration, and History of Discoveries: Society of Mining Engineers, 374 p.
Hausel, W.D., 1994, Economic geology of the Seminoe Mountains greenstone belt, Carbon County, Wyoming: Geological Survey of Wyoming Report of investigations 50, 31 p.
Hausel, W.D., 1996, Pacific Coast diamonds-an unconventional source terrane in Coyner, A.R., and Fahey, P.L., eds., Geology and ore deposits of the American Cordillera, Geological Society of Nevada Symposium Proceedings, Reno/Sparks, Nevada, p. 925-934.
Hausel, W.D., 1998, Diamonds and mantle source rocks in the Wyoming Craton, with a discussion of other US occurrences: Wyoming State Geological Survey Report of Investigations 53, 93 p.
Hausel, W.D., 2001, Placer and Lode Gold Deposits: International California Mining Journal, v. 71, no. 2, p. 7-34.
Hausel, W.D., 2006, Minerals & Rocks of Wyoming, A Guide for Collectors, Prospectors and Rock Hounds, WSGS Bulletin 72, 125 p.
Hausel, W.D., 2009, Gems, Minerals and Rocks of Wyoming. A Guide for Rock Hounds, Prospectors & Collectors. Booksurge, 175 p.
Hausel, W.D., and Hausel, E.J., 2011, GOLD - Field Guide for Prospectors and Geologists - Wyoming Examples. CreateSpace, 366 p.
Hausel, W.D., and Sutherland, W.M., 2006, World Gemstones: Geology, Mineralogy, Gemology & Exploration: WSGS Mineral Report MR06-1, 363 p.