Monday, December 23, 2013

Prospecting for Gemstones

Searching for & finding gold in the Silver Crown district in Wyoming in 2012.
As a gold or gemstone hunter or prospector, you must understand geology and chemistry of rocks while keeping an eye open for a variety of gemstones, precious metals, base metals and diamonds. Sorry, it takes years to understand rocks and their chemistry, but I've tried to provide prospectors and rock hounds with information they can understand in my webpages, blogs, blogspots, Google+, books and other publications. Heck, even I have a hard time understanding many geology professors when they add unnecessary jargon to confuse issues.  Before they give any one a PhD, they should ask the candidate to provide examples of their communication skills with the general public.

All of those valuable gemstones and gold found in rocks are related to chemistry of the rocks, invading fluids, and geological history. For example, if you look for gemstones with considerable aluminum - such as ruby and sapphire - look for host rocks that have lots of aluminum (mica-rich schists, etc) to contribute; or evidence that aluminum-rich fluids migrated through fractures. Then look at the past geological history - how deep were the rocks buried in the past (if at all), when did they uplift, how much erosion occurred, etc. I know this type of information is difficult to come across, but any clues will help. 

Years ago, I worked for the Wyoming Geological Survey at the University of Wyoming in Laramie. While working on a research project with the Department of Engineering in 1980, I began to search for disseminated gold and base metal deposits for the department. The University of Wyoming engineers were interested in conducting metallurgical and chemical studies for metal extraction in disseminated deposits. So, I examined the areas in Wyoming that potentially could have these types of deposits based on geology. I knew I needed some good source rocks for the gold and also some  volcanic rocks that were very hot in the geological past and this took me to only a couple of places - Mineral Hill in the Black Hills, Bear Lodge Mountains in the Black Hills, the Silver Crown district in the Laramie Mountains, the Rattlesnake Hills in the Granite Mountains, the Absaroka Mountains bordering the eastern flank of Yellowstone, and Yellowstone. Unfortunately, Yellowstone and the Absaroka Mountains were off limits since the Feds had withdrawn them from mineral exploration even though some of the rocks in this area are likely rich in gold. Oh well.

Two places I thought had very good potential for this project included the Rattlesnake Hills in central Wyoming, where I discovered an previously unknown gold district and investigated a large jasper deposit with some actual leaf imprints, and the other was the Copper King mine in the Silver Crown district where a sizable gold-copper resource occurred in a deeply eroded porphyry copper deposit of Proterozoic age (about 1.4 billion years old) that had been uplifted and exposed at the surface just a few miles outside the town of Cheyenne.

The GemHunter spent more than 30 years searching the hillsides for
gemstones and gold in Wyoming for the Wyoming Geological Survey
as well as for several mining companies in and outside of Wyoming. He
was the most successful geologist in the history of Wyoming for making
new discoveries and published around 1000 books, magazine articles,
maps, professional papers and abstracts. Now you can have your own
consultant - in a book! This 369-page book tells you where and how to
find gemstones in Wyoming and in some nearby areas. In many
cases he gives you GPS coordinates to find these sites on Google Earth.
When you are ready to take a weekend field trip, all you have to do
is convert the GPS coordinates to your hand held GPS unit and it will
lead you to hundreds of gemstone and gold deposits. Already, many
people have reported finding gold, labradorite, jasper, agate, opal,
rubies, sapphires, iolite and diamonds by using this book. And one
person even panned out many diamonds including one of the largest
ever found in Colorado - weighing about 5 carats! So, why wait for
everyone else to find the treasure that could be yours. To convert your
Google Earth GPS coordinates to your hand held, just click on the
GPS conversion box at the top of the Gold Prospecting blogspot.
Yes, that's me (above photo), working for Saratoga Gold and Strathmore Resources as an independent consultant looking for additional gold resources at their 2 million ounce gold-equivalent gold-copper deposit known as the Copper King in the Silver Crown district near Hecla, Wyoming. And I believe I found a continuation of their gold deposit by 'reading' the rocks: it was down-dropped along a fault in the geological past and now lies under shallow, alluvium-covered basin to the east of the primary deposit. So, within reach of Cheyenne, there is a minimum $2.6 billion ($1,300/ounce gold price) gold-copper deposit with much of it sitting at the surface and an untold amount of gold remaining to be drilled. AND, for those of you who like to pan, streams that drain this deposit will likely have some gold, particularly near the deposit. After millions of years of erosion, some of that gold should have been carried downstream. So, check the area, check the topographical maps, check Google Earth (41°8'42"N; 105°11'11"W) and start looking for gold and diamonds! But please don't trespass on private property.

It is interesting that the Copper King is deeply eroded based on its geological history - and so are the kimberlite pipes in the Colorado-Wyoming State Line district to the west along Highway 287 as well as the cryptovolcanic structures that lie in between. So, you might take a gold pan, find some public access, and then pan for gold and diamonds. Both will likely be found in a drainage or two in the area. And yes - I know most are dry drainages, so you may have to transport some dirt to water, or vise versa, or learn how to dry pan. When I taught prospecting short courses through the School of Extended Studies at the University of Wyoming, I periodically taught this technique. It works great in Wyoming because of all of the wind, but it also leaves you very dirty. So why hasn't anyone done this before? Good Question.

Not far from from the Copper King, I identified more than 50 cryptovolcanic structures that likely include one or more kimberlite pipes for an Australian diamond company (DiamonEx). Many kimberlites are known as sources of gem and industrial deposits. To see some of these structures, just use Google Earth and do a search for Twin Mountains Lakes, Laramie County, Wyoming and you will see an area on the areal photography that shows a major regional fold in the old Precambrian rocks with several, distinctly rounded to elongated lakes. Google Earth also provides different ages of photography, so take a look at the 1999 and 2002 vintage photos and you will see the lakes have what appears to be a white salt in the soil. If this is carbonate - it may have been derived from kimberlite as the old, folded Precambrian rocks are a poor source for calcium carbonate. You can test soils like these with 10% hydrochloric acid and the acid will free carbon dioxide and the soil will fizz like soda pop! But beware, our incredibly non-intelligent government expects to outlaw carbon dioxide. Seems that politicians are looking to fill their pockets with money over carbon credits.

So, how dangerous is this carbon dioxide - you tell me the next time you drink a soda, exhale, or walk outside among the trees and grass. How is it that we keep electing dumber and corrupter politicians? Ha! Its because the only people who run for office are sociopaths and pathological liars. Back to the rocks. I found similar depressions (structurally controlled all over this region in Colorado and Wyoming - actually more than 300!

Large microcline feldspar crystal from Copper Mountain in the Owl Creek
Mountains of Wyoming. Although this crystal is white, many of the feldspar
crystals in the State Line pegmatites are pink to brown orthoclase feldspar.
Just west of these crypto volcanic structures, I found a few diamond deposits from 1977 through 1980, in the State Line district where several other diamond deposits had already been found associated with a rare rock known as kimberlite. Most of these were found by David Eggler, Mac McCallum and Chuck Mabarak.

So, what is a crypto volcanic structure? It is a structurally controlled depression that looks similar to an impact feature. And, who knows, some could be impact features. Years ago, I looked at one such anomaly in Kansas known as the Winkler Crater. This feature (39°29'25"N; 96°49'13"W) was initially identified as an impact crater until Doug Brookins spent some time on the ground and discovered the crater was filled with kimberlite instead - so it was a kimberlite pipe (volcano). Years later, Cominco American Mining Company tested the pipe and reported finding one micro-diamond in the kimberlite. And you can still see this anomaly on Google Earth. It is perfectly round, has a deeper green color due to the vegetation growing over the kimberlite, and you can still see the scars of the trenches dug in the kimberlite by Cominco American many years ago.

Smaller microcline feldspar crystal from Copper Mountain.
For those who might be interested; there are some pegmatites in the area between the Copper King and Highway 287. Pegmatites are dike-like, very coarse-grained granitic rocks. And most of those found in this region have considerable milky white quartz that prospectors call 'bull quartz'. Not sure why they call it bull quartz. Anyway, some of these can be seen along Highway 287 south of Laramie (41°1'57.73"N; 105°26'3.95"W) and a few were mined during world war II for their coarse-grained feldspar crystals. I was told that the feldspar was used to manufacture false teeth. Look for some old mine cuts and also on Google Earth, you can spot these by their white quartz! So, look for the white quartz and also look for any piles of blue ground that might be kimberlite.

Anyway, in some of these pegmatites, you will also find some coarse-grained mica books, rare yellow-green, translucent to frosted beryl, and an occasional garnet - I found one crystalline garnet in the pegmatite off of Highway 287 that was 6 inches across - but the color and transparency were ugly! But the quartz is interesting. Periodically, one can find small, transparent, hexagonal quartz prisms in rock fractures, but most of the quartz is the bull quartz. The bull quartz in these pegmatites express piezoelectric characteristics very well.

Of course, someone will think you are totally crazy for doing this - but what the heck. Most of us rock hounds are a bit nuts. Take a large piece of the bull quartz in a dark closet (large so you don't miss and smash your toes) and hit it with a hammer. You will be able to see a very nice spark generated within the quartz. Pretty neat! But again, whoever gets curious and opens your closet door is probably going to call for a straight jacket.

Hope this blogspot helps you find a treasure - and in the following pages, I tell you about jasper, agate, and quartz. So, go fill up your back packs and let me know when you find a diamond or two or a few nuggets, but respect the private land owners - The GemHunter