Tuesday, January 29, 2013

Green Rocks and Minerals

This past fall, I was working on a gold project near Cheyenne, Wyoming and met two old friends for dinner. One had an affection for green minerals and rocks, so I thought I would tell you a little about some green rocks in my back yard.  One specimen has a lot of lumps and kind of reminds me of brains. So I call it jaded brains. It has a pleasing light-green color and was picked up in the jade fields of Wyoming.

Light green jade
The geological and geochemical processes that produced jade are intriguing. The jade fluids produced under great pressure (and temperature) tended to replace much of the original rocks and minerals to produce jade. Each atom of the original mineral or rock was mobilized and replaced by the atoms that make up jade. We don't know if this was a rapid process or a process that took place over millions of years.  But we can see the results and sometimes, much of the original rock matrix was replaced by jade leaving feldspar phenocrysts (larger crystals in a fine-grain groundmass or matrix) somewhat in tact.  In other specimens, we find quartz crystals that are preserved and untouched, but in others, even the quartz is not safe, as we find evidence of quartz (hexagonal) being replaced by jade.

Jade porphyry. Much of the original rock matrix was replaced by jade leaving some greenish white feldspars in place that are also partially replaced.


Jade specimen with quartz crystal preserved.

Monday, June 11, 2012

Wyoming - The Gemstone State.

Gem-quality pyrope garnet faceted from rough collected at Butcherknife
Draw near Green River, Wyoming.
Colored gemstones were almost unheard of in Wyoming prior to 1977 other than some fabulous cobbles and boulders of jade, some petrified wood, a few agates and a couple of tiny diamonds that required a microscope to see. After I was hired as the Senior Economic Geologist at the Wyoming Geological Survey, I began first to search for diamond deposits, then gold, and along the way, I got interested in gemstones, their geological settings and necessary conditions for formation (chemistry, pressures and temperatures) (Hausel and Sutherland, 2006). It soon became clear that several variety of gemstones should be found in Wyoming but few were ever reported. So I went looking and was amazed at all of the gems, diamonds and gold that had been overlooked in the Cowboy State. And I can guarantee there is a lot more, but it seems like nothing is being done since I left Wyoming in 2007 even though I had found evidence of hundreds of more diamond deposits, gold deposits, a few palladium deposits, several ruby deposits, more iolite deposits and possibilities for emeralds and other beryl deposits (aquamarine and helidor) just to name a few.
Model posing with transparent
jade in necklace.
Over the years, I mapped more than 1,000 km2 of complex Precambrian geology along with mapping some younger volcanic terrains: it became clear that Wyoming should have a wide variety of gemstones - but there were few reports of gems being found in the State and little evidence that anyone had been or was looking. After I formulated some ideas on what to look for I soon started making discovery after discovery. Along with my discoveries, some rock hounds were also making interesting discoveries. If only I could have been allowed to continue searching, I would have made many more discoveries.

I found dozens of gemstone deposits and possibly the largest colored gemstone deposit on earth. I recovered the largest iolite gemstones on earth (one weighing >24,000 carats and left some in the outcrop that would dwarf these giant gemstones. A few left in outcrop I estimated would weight >100,000 to 1,000,000 carats!). I also found evidence for additional ruby and sapphire deposits in the central Laramie Range, Granite Mountains, Owl Creek Mountains and southern Wind River Mountains after finding seven previously unknown ruby deposits. And I began chasing more opal deposits where ever the countryside had been blanketed by Tertiary to Recent ash falls from past eruptions from the Yellowstone caldera (I had already found one of the largest opals on earth that weighed more than 77,000 carats with larger stones left in the field and also found a large deposit of fire opal). I was searching for other gems including possibilities of emeralds in the Sierra Madre and Overthrust belt, investigating enormous amounts of sky blue kyanite, looking for more iolites, rubies, sapphires and aquamarines, and I had verified Colorado, Montana and Wyoming was underlain by a major diamond province.
Gem kyanite from Laramie
Range
It was clear, due to the unusual geology of Wyoming being a craton that was underlain by (1) very old Archean rocks (rocks greater than 2.5 billion years in age) that were subjected to very high pressures and temperatures resulting in their recrystallization and (2) some younger Proterozoic (2.5 billion to 600 million years in age) schists
and granites that had a wide variety of mineralogy and chemistry that were also subjected to high pressures and temperatures, (3) younger Phanerozoic (less than 600 million years old) sedimentary rocks, (4) Tertiary and Quaternary volcanic rocks and ash falls and (5) rare kimberlites, lamproites and lamprophyres (subjected to extreme pressures), that Wyoming had many potential favorable host rocks for a large variety of gemstones – but no one had bothered to look.
Fancy diamonds found in Australia and predicted for Wyoming
and Colorado

I began to search for different gemstones keeping in mind the geological environments and the rock chemistry. I started to make lists of what I might find and kept extensive files on various gemstones and their geological environments worldwide. While I was mapping, I was also searching for gold, base metals, strategic metals, gemstones and decorative rocks. Soon I was finding many gemstones on my list. Here is the list of what I started searching for and finding in many cases:
Giant jade boulder from Jeffrey City, Wyoming.
Agate, aquamarine, almandine, andalusite, andradite, amethyst, apatite, azurite, ammolite, apache tears, amber, ametrine, barite, bloodstone, blue chalcedony, bronzite, burgundy diamond, canary diamond, carnelian, chalcopyrite, champagne diamond, cherry opal, chocolate diamond, chromian diopside, chromian enstatite, chrysoberyl, chrysocola, chrysoprase, citrine, common opal, clinozoisite, cuprite, dendritic gold, nugget gold, platinum, palladium, drusy quartz, emerald, epidote, fire (mexican) opal, fluorite, fuchsite, garnet, gold, golden beryl, golden sapphire, goshenite, green aventurine, green tourmaline, heliodor, hiddenite, idocrase, iolite, jade, jade pseudomorphs, jasper, jasperoid, jasper breccia, kunzite, kyanite, labradorite, lemon serpentine, lepidolite, malachite, maxixe, black opal, moonstone, morganite, moss agate, onyx, oriental sapphire, peridot, pink diamond, pink sapphire, precious opal, prehnite, pyrite, pyrope, quartz, rock crystal, rose diamond, rose quartz, rubellite (pink tourmaline), ruby, rutilated quartz, rutile, schorl, specular hematite, scapolite, sillimanite, silver,  smoky quartz, sodalite, spessartine, sphene, sphalerite, spodumene, star sapphire, tanzanite, tourmaline, tigerseye, varisite, white sapphire, zoisite and zircon.
A 12-carat, nearly flawless, rough pink sapphire recovered from the Palmer
Canyon deposit by Vic Norris.
The more I searched, the more I found. I also spent time educating rock hounds, prospectors, companies, geologists and mineral collectors in Wyoming and nearby states by providing lectures, short courses and field trips on how, where and what to prospect for. I also wrote many articles and books on prospecting: it was working. Soon I was not the only person looking for gemstones and others began searching and finding gems in the Cowboy State. Over 3 decades, I found nearly 75% of the gemstones on my list and I suspect if I would have been able to continue my research, I would have found many more deposits and possibly as many as 85 to 90% of the gems.

Flawless pyrope garnet I collected at Butcherknife
Draw, Wyoming and sent to Sri Lanka for faceting.
I was in demand to give talks all over the country and many people were showing up to my lectures carrying all kinds of minerals and rocks previously unreported in Wyoming including things like gem-quality labradorite found in road bed material from Albany County 11 and 12 where I had recently found a breccia pipe with limestone xenoliths adjacent to a significant kimberlitic mineral indicator anomaly that we had identified prior to 1988. Others found diamonds in anthills in the Green River Basin and a few showed up with beautiful specimens of gold nuggets (one person had more than a hundred high-quality nuggets from South Pass and another showed me ball jars full of gold nuggets and dust from the same region), jasper and agate.

I had found many previously unreported kimberlites and kimberlitic indicator mineral anomalies in the Iron Mountain district near Chugwater and this attracted prospectors to dig for diamonds. I visited the Great Diamond Hoax area in northwestern Colorado where I recovered diamonds, rubies, and pyrope garnets salted by scam artists in 1872. But then I was told by a geologist that Diamond Peak actually had conglomerate containing gem-quality pyrope garnet and chromian diopside (both diamond indicator minerals). What was the chance of this happening? 

Diamond companies started to show up in Colorado, Montana and Wyoming. And the Kelsey Lake diamond mine opened on the border south of Laramie - but soon closed due to legal problems. Other companies picked up other properties in the same area and found enough diamonds for commercial production. Between 2004 to 2006, the Wyoming Geological Survey was decimated by a sociopath who is still on the loose. For ethical and a reasons, I decided to take early retirement and run US exploration for DiamonEx Ltd, an Australian Mining Company with interests in Botswana. And I had a wonderful time until the market crash of 2008, which put several small mining companies out of business.
Gem kyanite cut into cabochons from Palmer Canyon, Wyoming.
There are literally hundreds of billions of carats of this gemstone
in eastern Wyoming at Palmer Canyon, Cooney Hills, Grizzly
Creek and likely in other areas of the state (Hausel, 2009). These and other
aluminum-rich minerals are often found in what geologists call metapelite
(mica-rich schists) that was subjected to moderately high pressures and
temperatures. Using this information, I found dozens of these deposits around
Wyoming. The colors and fractures in these gems actually enhance their
appearance. I am very surprised that someone has not tried to market these
as they are relatively easy to cut. They are a low value gem, but when there
are billions of carats - who cares.
While at the Wyoming Geological Survey on the University of Wyoming campus, I had received regional and national awards for communication skills including the American Association of Petroleum Geologists President's Certificate and the Wyoming Geological Association's Distinguish Service Award for my research on Wyoming's geology and for the dozens of talks I had presented at that society. I had also been twice nominated for the Dibble Mapping Award by two former directors of the Wyoming Geological Survey - Gary Glass and Dr. D.L. Blackstone, Jr. The Laramie Lycem had presented me Distinguished Speaker of 1994 and the University of Wyoming Department of Geology & Geophysics included me as Distinguished Lecturer and these were just some of the national and international recognition I had received over the years for being a great communicator. When I was in college at the University of Utah, I had been employed as an astronomy lecturer at the Hansen Planetarium because of communication skills. But what the heck, what did all of these people know including Who's Who in America, Who's Who in Science, Who's Who in the World, 2000 Notable American Men, etc.

I was considered to be one of the few specialists in Archean gold deposits, diamond deposits, colored gemstone deposits, greenstone belts and more. I was told by the chairman of the Geology Department at UW, that it was only because of my work and research that geologists had a good grasp of the Precambrian Geology. I had been awarded and inducted into two different Halls-of-Fame (nominated for a third) for my geological research, education efforts and communication skills, something that I suspect no other geologist in Wyoming (and possibly the US) could claim.

Giant ruby found in the Granite Mountains. This was at one time the largest ruby ever
found on earth - but unfortunately, much of the ruby (purple red) was replaced by zoisite
and fuchsite (green matrix). However, it suggests that exploration of this deposit will
potentially result in discovery of some of the largest rubies on earth.
I had found one of the largest gold deposits in North America, found a whole new gold district with commercial gold mineralization, studied hydrothermal alteration characteristics associated with a large dissimated gold and copper deposit, identified more than a hundred gold anomalies, dozens of gemstone deposits, a couple of massive sulfide deposits, one of the few nickel anomalies ever to be found in Wyoming with some palladium and platinum and more (for which I gained nothing other than recognition and my personal education). I mapped nearly every mining district in Wyoming along with the two largest kimberlite fields in the US and the largest lamproite field in North America, and I was in demand as a consultant for mining companies when I took annual leave from the Survey.

It was time to move on, so I went to work as VP of US Exploration for DiamonEx Ltd, where I found some diamond bearing kimberlites, identified several hundred possible kimberlites for the company to explore and drill.  After DiamonEx, Ltd, I worked as a consultant for other mining companies including Black Range Resources, Giant King Gold, Strathmore Resources, Wyoming Gold, Saratoga Gold and others. Personally, I love geology and I love hunting for new mineral deposits.

Transparent blue barite from Shirley Basin, Wyoming.
Cape Emerald from State Line district, Wyoming
Banded Jasper from Tin Cup district, Wyoming
1.1 carat faceted ruby from Palmer
Canyon, Wyoming
Enormous ruby faceted from rough collected in the Laramie
Range, Wyoming
Cabochon of specularite with copper from Charter Oak mine,
Wyoming
Gem labradorite from Sybille Canyon,
Wyoming.

Malachite with specular hematite from the Hartville area, Wyoming




Sunday, October 9, 2011

Geology of Gemstone Deposits

Much of Wyoming is underlain by Archean cratonic basement rocks and cratonized Proterozoic rocks that provide favorable geological environments for a variety of gemstones – notably diamond, iolite, ruby, sapphire, garnet, kyanite, andalusite, sillimanite, labradorite, jewelry grade gold, platinum and palladium nuggets, emerald, aquamarine, helidor, tourmaline, spinel, clinozoisite, zoisite, apatite, jasper, specularite, etc. Thick Phanerozoic sedimentary rock successions with lesser Tertiary volcanic rock cover large portions of the basement terrain. Some of these Phanerozoic rocks provide favorable hosts for other gemstones including opal, placer diamond, placer gold, placer platinum, placer ruby, jasper, agate, emerald, varisite, etc.


Using traditional exploration and prospecting methods, dozens of gem and precious metal deposits were discovered over the past 3 decades, including major discoveries and geological and mineralogical evidence for significant undiscovered deposits. Major swarms of mantle-derived kimberlite, lamproite and lamprophyre, many of which have proven to be diamondiferous, also host colored gemstones including pyrope garnet (Cape Ruby), spessartine garnet, almandine garnet, chromian diopside (Cape Emerald) and chromian enstatite. One lamproite also yielded peridot.

 Favorable conditions for crystallization of metamorphogenic gemstones during regional amphibolite-grade metamorphism occurred during the Precambrian. In this terrain, metapelite in the central Laramie Range hosts kyanite, sillimanite and andalusite. These three minerals provide evidence of favorable pressures and temperatures needed for crystallization of aluminous gemstones including ruby, sapphire and kyanite. Cordierite (iolite) another aluminum-rich gemstone, formed during a later thermal event. This later event was responsible for deposition of world-class iolite (Water Sapphire) gemstone deposits.

While searching for gold, I
came along this giant jasper deposit.
Evidence for undiscovered gemstone deposits is predicted based on mineralogical anomalies detected during various research projects from 1977 until 2005. These include ruby, sapphire, gold and aquamarine found in stream sediment samples as well as favorable geological terrains that remain unexplored. Other anomalies include pyrope garnet (several with G10 geochemistry), picroilmenite, and some chromian diopside that provide evidence for hundreds of undiscovered diamond deposits. Elsewhere, detrital diamonds reported by various prospectors provide direct evidence for undiscovered diamond deposits. Other geological and mineralogical evidence suggest the presence of additional undiscovered opal, cordierite (iolite) and kyanite deposits. Wyoming could potentially become a major source for gemstones including diamond, gold, platinum, palladium, Cape ruby, Cape emerald, iolite and opal.

Giant chrome diopside gem in kimberlite from Colorado.

Wednesday, August 12, 2009

NEWSLETTER

Prior to 1975, only jade and a few agates were known in Wyoming. But from 1975 to 2007, Wyoming became known as the gem capital of North America and now has a very impressive list of gemstones and the widest diverse collection of documented gems of any state in the US. A few are considered world-class and have yielded some of the largest gemstones in the world. The collection of gems in Wyoming now include agate, jasper, common opal, fire opal, precious opal, onyx, gold nuggets, Cape Ruby (pyrope garnet), spessartine garnet, Cape Emerald (chrome diopside), chrome enstatite, kyanite, iolite, ruby, sapphire, peridot, diamond, specularite, apatite, minyulite, amethyst, aquamarine, jade, almandine, chalcedony, silicified banded iron formation, jasperoid, labradorite, grunerite, amber, chrysocolla, heliodor, varisite and others (Hausel, 2008c; Hausel and Sutherland, 2000, 2006).

See our companion websites at GEMHUNTER and GEOLOGY.

Our 2009 book, 'Gems, Minerals and Rocks of Wyoming' describes many of the minerals, gems and rocks found in Wyoming and will give you a start on this fun and potentially profitable hobby.

We just finished a book on gold (2011) which will tell you exactly where to go to find dozens and dozens of gold deposits. Find it at Amazon. Don't get left behind! This 366 page book tells it all!



Wednesday, December 31, 2008

DIAMONDS, DIAMONDS & MORE DIAMONDS

I love searching for diamonds. My first chance to explore for diamonds deposits occurred in 1977 when I was hired by Dr. Dan Miller of the WGS to appraise the newly discovered district south of Laramie. I ended up mapping the State Line district, found 9 diamond-bearing kimberlites my first 2 years & later mapped the Iron Mountain & Sheep Rock districts and the Leucite Hills lamproite field and explored for diamonds for some US companies, an Australian company and some Canadian companies. In fact, I was promoted to US Exploration Manager and later VP of DiamonEx USA for DiamondEx Ltd (see GEMHUNTER).

I found lamprophryes in Montana & Wyoming & identified several hundred cryptovolcanic structures within & surrounding the State Line that are likely diamond deposits (these remain unexplored). A few of these include Indian Guide, Twin Mountain, Happy Jack & others. I expanded my research & found similar cyptovolcanic structures in Canada & even in the Kimberley region of South Africa. I found a major district of 50+ anomalies sitting along the interstate in the US!

Photos - Above, gem diamonds from Kelsey Lake, Colorado, vegetation anomaly over kimberlite at Iron Mountain, and exposed blue ground in highwall at Kelsey Lake. Below, 14.2 ct flawless octahedron from Kelsey Lake, aerial photo over the Ekati diamond mine in Canada (one of 5 major mines developed in Canada since 1998), carbonate-stained soil over cryptovolcanic structure, and view of one of the Lost Lakes cryptovolcanic structures.

 
Commercial deposits occur in placers, kimberlite and/or lamproite & I'll bet other commercial deposits will be found in lamprophryre in the future. The diamond deposits south of Laramie were in kimberlite & placers. The kimberlites are deeply eroded & spilled millions of diamonds into the surrounding streams, but no one has ever systematically looked for diamond in the creeks (even so, diamonds were accidentally recovered in Rabbit Creek and hundreds were recovered in George Creek, and several including a 6.2 carat diamond were recovered in Fish Creek, but the rest of the streams are UNPROSPECTED!

Kimberlite is a ultrabasic, potassic igneous rock that erupts along fractures from 90 to 120 mi depths. They typically occur in very old cratons & cratonized rocks (basically ancient continental cores that consist of >1.5 billion year old granite, gneiss & schist). The magma, under pressure rises rapidly from the mantle because of the great depth & because of considerable water vapor & carbon dioxide under pressure. Some suggest gaseous emplacement velocities of kimberlite are on the order of Mach 3. The eruption is relatively cool: CO2 gas expands cooling the magma such that emplacement temperatures of 32 degree F are not uncommon. This collection of unusual characteristics results in small, circular maar-like volcanoes (without cones) & dikes that are structurally controlled.

Gem diamond with excellent characteristic trigons on surface
Things to keep in mind: kimberlite will serpentinize because of water vapor, this produces a relatively soft rock that erodes faster than surrounding country rocks & usually results in a depression with different vegetation than the surrounding rocks. These depressions may contain shallow ponds. They are structurally-controlled such that >one anomaly is often found in a line. Because of calcium carbonate in kimberlite, carbonate will leach out into the pond staining the soil white. Keep in mind that salts are not all that uncommon in basins where lots of young sedimentary rocks occur with considerable carbonate. But in the craton basement (i.e., mountain ranges of Wyoming) there is no known source for carbonate, so if you spot a structurally-controlled lake surrounded by salt in old Precambrian rock, you might want to find out why? And if you find one, typically, with effort, you will find others along the same structure.

Diamonds found in Colorado & Wyoming ranged from microdiamonds to 28.3 cts & included one chip from a 80- to 90-ct stone. Some believe there are no commerical deposits in this area, but all mills were so poorly designed they rejected all diamonds of any size. For example, the Kelsey Lake mill rejected anything weighing >40 cts! It also rejected most diamonds under 40 cts such that when the tailings were tested in 1997, the first sample yielded a 6.2-ct stone! The grades of several kimberlites were high, the gem:industrial ratios were good & diamond values were reasonable. The biggest problem with the State Line district was good diamond companies with diamond expertise were in short supply.

CAPE RUBIES, CAPE EMERALDS, GARNETS

Diamonds were discovered in Wyoming & Colorado in 1975 by Mac McCallum, Chuck Mabarak & the USGS. This lead to some exploration for diamonds. Associated with diamonds are a host of extremely rare mantle nodules & gemstones known as Cape Ruby (pyrope garnet), Cape Emerald (chromian diopside & enstatite) that are always overlooked by mining companies. Yet these are very attractive, value-added gemstones. With some marketing skills, could potentially capture large parts of the colored gemstone market. For example, many Cape Emeralds are much more saturated & beautiful than emerald.
These gems were found by many prospectors and geologists all over Wyoming & northern Colorado. Large areas in the Green River & Bighorn Basin contain these diamond indicator minerals, yet little exploration has ever occurred for these or their source rocks.
Photos - Diamond indicator minerals from Sloan kimberlite, Colorado, & faceted pyropes from Green River Basin, Wyoming & Kyanite Eclogite from the Aultman 2 kimberlite, Wyoming.

GOLD & OTHER PRECIOUS METALS

Little was known about gold in Wyoming, thus I set out to map, evaluate & find more. I discovered gold everywhere I looked. I was amazed at how much had been overlooked. I published compendiums that are used by prospectors & geologists & mapped several mining districts that were previously unmapped or only partially mapped. I even found a previously unrecognized ultramafic massif with significant palladium, nickel gold & copper mineralization & a whole new district.

I have many great stories & memories about discoveries & prospectors I met. Hopefully, I will be able to find time to write a book about these, as such stories should be preserved. There are stories about hundreds of nuggets in ball jars in Shorty Haddenham's trailer at Atlantic City, dozens of nuggets found by a Ft. Collins prospector, a prospector who spent one entire winter jumping a claim & panning out barrels of mica thinking he had found the Mother Lode & my research along the UP corridor- we found gold everywhere including the Laramie City dump.

Gold photos below - 34 oz nugget (Rock Creek, South Pass), gold from Douglas Creek, and gold from Dickie Springs (South Pass).

I mapped the South Pass greenstone belt at the southern tip of the Wind River Mountains which included several historic gold districts: Lewiston, South Pass, Atlantic City, Miners Delight & others. I identified several hundred gold anomalies & found gold was structurally controlled in reef ore shoots that are very rich down plunge. One deposit I mapped (Carissa) is a major deposit 1000 ft wide, 1200 ft long & probably continuous a few thousand feet downdip. This deposit was withdrawn by the legislature without any scientific review - such abuse of political power literally took away a mountain of gold & many good jobs.

Geology led me to many discoveries. The Rattlesnake Hills were an obvious target, so in 1981, armed with the concept that the RH were part of a fractured greenstone belt intruded by Tertiary alkalic volcanic rocks, I knew there had to be gold. And I found gold in the RH in veins, shears, Tertiary breccias, stockworks, pyrite. I also found significant gold elsewhere in Wyoming - Seminoe Mountains, Mineral Hill, Purgatory Gulch, more.

Left - Gold at the end of the rainbow at the Duncan mine, & view of part of the auriferous shear at the Carissa - a major gold deposit with potentially >US$billion in gold.

OTHER GEMS

During 30 years at the WGS, I found hundreds of deposits. How did I do this? I used geology as a guide; I looked at things differently and was motivated to look and search for mineral deposits.

While conducting reconnaissance, I discovered jasper in several old mines at Tin Cup, in an outcrop near the south edge of the Rattlesnake Hills, and found jasperoid at Quaking Asp Mountain. Some of the Tin Cup jasper is extraordinary and found in masses weighing several hundred pounds. The jasper in the Rattlesnake Hills contained some fossil leaf imprints.


Nearly everywhere I explored, I followed trends and examined geology which lead me to other mineral deposits. I was curious enough to find out what some of the unusual minerals were that I picked up, and as a result, I identified more than a dozen minerals that had never been reported in Wyoming.
Above - barite from Mine Hills, Shirley Basin. Middle- a group of cabochons cut from various material. Below - beautiful jasper from Tin Cup & me standing in old prospect pit. These prospects were reported as having high-grade gold values. I found no gold & likely these were left over from various gold mining frauds and scams from the 1800s. Note the large mass of jasper to my right (probably a few tons of high quality material).




Left - Labradorite feldspar collected by Norma Beers in the road bed of Albany County 12 in Albany County. This is just one of millions of gem-quality feldspar found in this area - yet this resource remains unexplored.