Barite Gems, Roses, and Crystals

Mine Hills blue barite gems, Shirley Basin, Wyoming (Hausel, 2014). These gemstones form
excellent, transparent blue, orthorhombic prisms with two directions of perfect cleavage, and
one imperfect cleavage. These make stunning specimens in mineral collections, but for some 
reason, these still remain untouched for manufacturing gemstones and jewelry.

Barite (BaSO4) (barium-sulfate), when found in crystalline form, may occur as attractive mineral specimens that will enhance any mineral collector’s or rock hound’s collection. Such crystals are considered principally industrial minerals and have a relatively low Moh’s hardness of 3 to 3.5, which means you can easily scratch it with a pocketknife. 

Most unusual is its relatively-high specific gravity (sg = 4.5) for a non-metallic mineral. It is high enough that one of the post important physical properties used to identify barite in the field, is its heft. After you return home, to your lab, or office, then you can confirm its specific gravity if necessary.

Blue barite, Mine Hills, Shirley Basin, Wyoming
(Hausel collection). These are some of the better
specimens found in the world, but remain to be
faceted into gemstones.

Density relates to mass per unit volume. The specific gravity is its relative density (weight of the mineral divided by the weight of an equal volume of water). Its high specific gravity produces noticeable heft, which aids in identification of barite. Heft is a relative measure of a minerals specific gravity, so that when you bounce a hand specimen in the palm of your hand, it will seem unusually heavy for size.

Barite is usually found as concretions or void-filling crystals in faults, fractures and in sedimentary rocks. It often occurs as concretions and veins in limestone, dolomite, and even sandstone. Wherever these rocks crop out on hill- or mountain-sides, erosional debris will accumulate at the base of the outcrop, potentially yielding a residual concretion deposit in soil and alluvium downslope from the rock.  

Barite may also occur in sand and sandstone. In some cases, concretions formed by crystallization of barite within interstitial spaces in sand or sandstone produce classical barite roses. And wherever fractures tap hot springs; sometimes barite, metallic sulfides, calcite and/or quartz are carried in hydrothermal fluids, and precipitate in fractures and faults.

When found in large tonnages in massive form, or as residual deposits, it may be mined and used in a number of different applications including drilling mud additive to aid in blowout prevention in oil and gas exploration due to its high specific gravity. 

Massive, fracture-fill barite, Laramie Mountains, Wyoming.

Barite crystallizes in the orthorhombic crystal system and exhibits tabular crystal habits parallel to the crystal base. Other habits include fibrous, nodular, massive and aggregates or divergent groups of tabular barite crystals. Barite exhibits perfect cleavage parallel to the base and prism faces. Minerals are often colorless, white, yellow, grey, brown and less commonly light shades of blue. Crystals are brittle, produce irregular fractures, and have vitreous to pearly luster. 

Barite is rarely used as gemstones, but some transparent, colored, specimens yield very attractive stones when faceted. However, because perfect cleavage and relative softness, the gemstone should be protected by jewelry mounts: daily wear is not recommended as it will easily scratch. Some of the more attractive blue barite in North America is found in the Mine Hills area of the Shirley Basin of Wyoming. Many crystals in this area are transparent and have pleasing, blue color; but, as far as the author is aware, these potential gems remain untapped for jewelry.

Crystals exhibit distinct right angle prismatic cleavage. Tabular white, yellow, grey, blue, red, or brown, opaque, translucent and transparent crystals have been reported.

Some of the more attractive specimens found in Wyoming are light aquamarine blue, transparent to translucent, thin tabular crystals compressed along the c-crystallographic axis. This compression produces distinctly large crystal faces. Individual crystals of the Wyoming aquamarine blue barite, occur as plates with distinct beveled edges. Perfect basal cleavage parallel to the c-axis lies perpendicular to imperfect prismatic cleavage parallel to the b-axis. Where found near the Mine Hills the Shirley Basin of southeastern Wyoming, the barite is in vugs in limestone enclosed by calcite and rarely prismatic quartz.

Wyoming Localities

Shoshone Canyon (SE section 5, T52N, R102W). Small radial clusters of white barite crystals are found in the Shoshone Canyon area of Rattlesnake Mountain, 4 miles west of Cody in northwestern Wyoming. Some crystals from in this area are reported to be one inch in length. This barite is associated with paleo-hot spring deposits and solution cavities in the Mississippian Madison Limestone.

New Rambler mine (SW section 33, T15N, R79W). Fine-grained to massive pyrite was reported with barite at the New Rambler copper-gold-palladium-platinum mine in the Medicine Bow Mountains west of the Rob Roy Reservoir.

Fault-fill, quartz breccia with barite, Hog Park, Medicine Bow
Mountains, Wyoming (Hausel collection).

Hog Park (NW section 2, T12N, R85W). A pod-like mass of barite, 40 feet wide by 300 feet long, was described to be associated with opal in the Hog Park area of the Sierra Madre Mountains several miles southwest of Encampment. The barite is found  along the northern edge of a shear zone in contact with pink to red quartz monzonite. When investigated by the author, no evidence of opal was found; but, white crystalline to massive barite was present.

Shirley Basin. White barite concretions are found in Shirley Basin northeast of the town of Medicine Bow. These are weakly fluorescent under long-wavelength ultraviolet light.

In addition to white barite, very attractive aquamarine blue barite crystals occur in the vicinity of Sheep Creek near Crystal Hill adjacent to the Mine Hills (section 10, T26N, R75W) along the southeastern margin of the basin and adjacent to the western flank of the Laramie Range. Mine Hills is situated on the Laramie Peak 1:100,000 topographic map and are accessed from the west from Shirley Basin (see also Shirley Basin 1:100,000).

The barite occurs as attractive light-blue, transparent to translucent, tabular crystals and is found with calcite and quartz in vugs in the Casper Formation near a massive psilomelane, manganite (manganese) and jasper replacements in the Casper Formation (Hausel, 2014; Hausel and Sutherland, 2000).

Mine Hills, vug-fill, blue barite, Shirley Basin, Wyoming. Note the crystal habit of these perfect,
tabular blue crystals with beveled edges (Hausel collection).

References

Dana, E.S., and Ford, W.E., 1949, A textbook of Mineralogy: John Wiley & Sons, 851 p.

Hausel, W.D., 2014, A Guide to Finding Gemstones, Gold, Minerals and Rocks: CreateSpace, 368 p. 

Hausel, W.D., and Sutherland, W.M., 2000, Gemstones and other unique minerals and rocks of Wyoming: Wyoming Geological Survey Bulletin, 267 p.

Sinkankas, J., 1964, Mineralogy: Van Nostrand Company, 585 p.

DIAMONDS - A Hard Gemstone and Hard to Find.

Diamonds in the Rough

DIAMOND FACTS - Did you know: (1) Diamonds were initially found in India hundreds of years before the birth of Christ? (2) Diamonds are mentioned in Sanskrit manuscripts 320 to 296 BC, in Buddhist works as old as 400 BC, and mentioned in the Torah and is also mentioned in the Holy Bible at least six times, and appears in the Book of Book of Exodus possibly written about 500 to 600 BC. But the term used for diamond is adamant and could refer to ruby or some other hard gemstone. For instance, diamonds were initially termed adamas (invulnerable stone) which cause confusion in interpretation of ancient manuscripts, which also uses this term to describe other hard gems including corundum (ruby). (3) Diamonds were first found in rivers in India, where placer diamonds were considered of value because of hardness. Based on our current knowledge of the geology of India, most of these diamonds were likely derived from erosion of olivine lamproite and lesser kimberlite pipes. (4) Legendary diamonds such as the Koh-i-Noor (105.6 carats) and Hope (45.52 carats) were recovered from India. (5) The largest diamond ever recovered is the Cullinan diamond (3,106.75 carats) and recovered from the Premier mine ( 25°40'29"S; 28°30'50"E) in South Africa in 1905.

DIAMONDS Ever wonder why diamonds are called 'ice'?  They look like ice, but this is not the reason. Diamonds are heat conductors, so if you ever have the opportunity to touch your lips to a large diamond, it will feel cool as the diamond conducts heat away from your lips - just like ice.

Diamonds are the most valuable commodity on earth based on dollar value per weight. Some have sold for many times the value of an equivalent weight in gold - such as the Hancock Red diamond that weighed only 0.95 carat & sold for nearly US$1 million. To put this in perspective, one carat weighs only 0.2 gram - equivalent to 0.007 ounce. Thus, this diamond was valued at >300,000 times an equal weight in gold! Several other pink to red diamonds have also been valued at nearly $1 million per carat.

Other priceless diamonds were purchased by Royalty or donated to Royal treasuries. Most notable are the diamonds cut from the Cullinun rough, the largest rough diamond ever found that weighed 3,106 carats. The gems faceted from the fist-size rough diamond are now proudly displayed in the crown jewels of England. 

Diamonds are found with other gems; however few companies ever bother with the associated gems even though many are extraordinary stones in their own right and even out-shine ruby & emerald. These other gems are known as Cape Ruby (pyrope garnet) and Cape Emerald (chromian diopside and enstatite), but their lower value than the diamonds results in the diamond mining companies ignoring these gems. This is unfortunate as many are beautiful colored stones.

So, where do diamonds come from? Diamonds are found in several rock types, but the primary commercial host rocks are kimberlite and lamproite [2]. And there are also secondary hosts known as placers that contain diamonds - like those found along the west coast of Africa. Diamond being extremely hard results in most gem-quality diamonds surviving transport in rivers, streams and even along coastal shores. Many coastal diamonds in Namibia are thought to have been carried by the Orange River over distances of as much as 600 miles from their source area.

The principal host for diamonds are rocks formed in the earth's mantle that are known as eclogite and peridotite that are carried to the earth's surface in magmas known as kimberlite and lamproite. The kimberlite magma, when solidified, is known as the rock kimberilte that often has many mantle and crustal nodules including eclogites and peridotites and was named after Kimberley, South Africa where many of the original commercial diamond deposits were discovered in the 19th century. Kimberlite magma ascends from the earth’s upper mantle from depths of 90 to 120 miles and then explodes at the earth’s surface to form small maar-like volcanoes and dikes. At the surface, the pipes (maars) appear as depressions and several have been mistaken for impact craters in the past - such as the Winkler crater in Kansas. Some occur as circular to elongate depressions with vegetation anomalies controlled by fractures, have blue ground (montmorillonite clay) and are so carbonate rich that their soils react to dilute hydrochloric acid by fizzing as they release carbon-dioxide gas. Most pipes are <0.5 mile in diameter.

 

Several hundred cryptovolcanic structures discovered in northern Colorado and southeastern Wyoming discovered by the author in recent years likely include some kimberlites. Only a few dozen have been examined in the field, and only one was ever drilled - so it is possible that there is a major diamond province in this region.

 

When I mapped Iron Mountain ('fly to Farthing, WY, 82009' on Google Earth where you will be 4 miles south of the district), State Line (use Google Earth to fly to 'Tie Siding, WY' where you will be located 3 miles north of the State Line district. Search search due south of Tie Siding along the State Line to see an elongated scar immediately south of Fish Creek, this is the former Kelsey Lake diamond mine) and Sheep Rock districts, as well as the Leucite Hills volcanic field, it was apparent that there likely were some hidden kimberlites and lamproites in these areas. In fact, in the State Line district, surface and aerial geophysical surveys identified buried kimberlite. The other districts were never explored by geophysical surveys for diamond deposits. The type of geophysics that seemed to work well included INPUT airborne surveys and EM ground surveys.

 

Areas that remain unmapped include Indian Guide (fly to 'Indian Guide, East Albany, WY 82201' & you will be 3 miles due east of the Indian Guide cryptovolcanic structures and due west of the Iron Mountain diamond district), Twin Mountain, Happy Jack & others where there are many cryptovolcanic structures that could be kimberlites. One of these areas known as Twin Mountain Lakes has 50+ cryptovolcanic anomalies within view of I-80 west of Cheyenne! Some may prove to be the largest kimberlites in North America if they can ever be tested. If you examine these on Google Earth, you will see circular to elongate depressions, some with apparent, white soils (carbonate). These are located within the Proterozoic Colorado Province formed of basement rocks including amphiboles and granites that are poor sources for carbonate. So the carbonates in these depression were derived from some other rock type (kimberlite?).

 

In the Happy Jack area, I identified a distinct depression many years ago that I named the Bowling Pin anomaly. Later, we found several other depressions nearby that included rounded granitic boulders and carbonate rich soils typical of kimberlite. While working for DiamonEx Ltd, we wanted to drill these anomalies, but the BLM would not grant us access so these remain unknown anomalies. 

Lamproites were mapped in the Leucite Hills in SW Wyoming: a few of these yielded diamond-stability chromites and could contain uncommon diamond. In one area, more than 13,000 carats of gem-quality peridot was recovered from just two anthills adjacent to one of these lamproites - known as Black Butte. This is exciting in that there is a strong correlation in diamond content and olivine (peridot) content of lamproites. But in most areas in the world where commercial diamond-bearing lamproites were found - such as the Argyle mine and also the Ellendale mine in Western Australia, the diamond-rich lamproites were eroded and buried by a thin layer of soil while barren to diamond poor lamproites with little to no olivine stood out as distinct volcanic hills. So, in the Leucite Hills, there is a good possibility that some diamond-bearing lamproites lay under a few inches to a few feet of soil.

 

Some lamprophyres also have diamond, such as the lamprophyres found at Cedar Mountain Wyoming and a few minette lamprophyres scattered around the world.

Many of the kimberlite and the lamprophyres have been deeply eroded. Those in the State Line district spilled millions of diamonds into the surrounding streams, but no one has ever systematically looked for diamonds in the creeks! Even so, with a trivial effort of placer prospecting, several diamonds were found in Fish Creek on the Colorado-Wyoming border including a 6.2 carat gemstone! In Rabbit Creek, Colorado next to the Sloan kimberlites, only very recently has someone panned for diamonds - and recovered several diamonds including one flawless gem of 5-carats! This area was originally prospected for gold in the 1960s by Frank Yassai who recovered gold and diamonds in the creek, but no one paid attention. Additionally, many placer diamonds were found in George Creek Colorado in the 1980s. Overall, less than 1% of the streams in the district have been prospected for diamonds and these likely host thousands if not millions of diamonds!

Kimberlite is a ultrabasic, potassic igneous rock that erupts along fractures from 90 to 120 mi depths. They typically occur in very old cratons (basically ancient continental cores that consist of >1.5 billion year old granite, gneiss & schist). The kimberlite magma rises rapidly from the mantle with considerable water vapor & carbon dioxide in the magma. Some suggest gaseous emplacement velocities are on the order of Mach 3. The eruption is relatively cool: CO2 gas expands to cool the magma such that emplacement temperatures of 32 degrees Fahrenheit are not uncommon. 

Keep in mind: kimberlite will serpentinize because of water vapor reacting with the abundant olivine in the magma, this produces a soft rock (serpentinite) that erodes faster than surrounding country rock & usually results in depressions that support different vegetation than surrounding rocks. These depressions may contain shallow ponds, or they may just be outlined by distinct vegetation anomalies. In the State Line and Iron Mountain districts, I mapped many kimberlites based on the lack of trees in forested areas that also had high stands of bluegrass with carbonate-rich soil and scattered kimberlitic indicator minerals (rounded pyrope garnet, rounded spessartine garnet, rounded almandine garnet, large hand-sized sheared and rounded almandine megacryrsts, emerald-green chromian diopside, chromian enstatite, chromite, rounded picroilmenite coated with white leucoxene, large hand-sized picroilmenite megacrysts, diamonds, rounded cobbles and boulders of granite, amphibolite and mantle nodules of eclogite, peridotite, pyroxenite, dunite, etc. These anomalies were always structurally-controlled such that more than one anomaly was found along lineaments. Because of calcium carbonate in kimberlite, carbonate will leach into a pond staining the soil white. In the craton basement (i.e., mountain ranges of Colorado, Montana, Wyoming) carbonate sources are rare, so if you spot a structurally-controlled lake surrounded by white soil in old Precambrian rock (in the mountains), you might want to find out why.

 

Diamonds found in Colorado & Wyoming ranged from microdiamonds to 28.3 carats & included one chip from a 80- to 90-carat stone. Some believe there are no commercial deposits in this area, but all 4 mills constructed in the past were poorly designed and rejected many diamonds of all sizes. For example, the Kelsey Lake mill was designed to reject anything weighing >40 carats! It also rejected a very large number of diamonds under 40 carats such that when the waste tailings were later tested in 1997, the first sample yielded a 6-carat stone!

 

The grades of some kimberlites were high, the gem:industrial ratios were good & diamond values were reasonable. The biggest problem with the State Line district was companies with diamond expertise was in short supply. Another problem appeared to be an overall lack of large diamonds (except at Kelsey Lake). Large diamonds are very important for commercial operations because of high value. If you are a fan of Gold Rush you will remember when one group of prospectors traveled to Brazil to mine gold and instead thought they hit it big with diamonds. If they would have known something about diamonds, they would have packed up immediately. Rough gem diamonds sell for $50 to $450 per carat (and may only average about $150 and the diamonds picked up on Gold Rush appeared to be smaller than a carat, thus they would have been very low value. After diamonds are cut, they can increase in value typically 2 to 5 times the rough value. When mounted in jewelry, we often see another value increase. But large diamonds like the one in the photo below (Figure 1) of 620-carats bring high prices and some large rough diamonds may fetch many thousands of dollars and in some cases $millions. Because of this, a working diamond mine needs large diamonds to offset the costs of building a mine and mill. 

 

Diamond is relatively easy to recognize, but there are very few prospectors, geologists or jewelers with experience in recognizing uncut (rough) diamonds. One of the easiest methods is to use a relatively inexpensive device marketed as a 'Diamond Detector' or 'Diamond Detective'. This measures the unique surface conductivity of a diamond. It is so easy to use that its rumored that even some politicians can be taught to operate this push one-button instrument.  

 

Diamonds are the hardest minerals on earth - the only other minerals that have similar hardness include lonsdaleite and carborado, both considered diamond polymorphs. Thus diamond will scratch essentially anything. But don't fall for that old trick of scratching glass.

 

Glass has a moh's hardness of only about 5.5 while diamond is 10. There are a lot of minerals inbetween these two (including quartz, the commonest mineral on the earth's surface) that will also scratch glass. This is why I thought it humorous when I received a call from a diamond prospector who claimed to have found thousands of diamonds - his method of testing was scratching his truck's windshield. Poor guy, I hope he can still see out his window. Diamonds also appear greasy, attract grease (which is one reason grease tables are used to extract diamond), and they have distinct growth plates on the crystal surfaces.

Associated with diamonds are a host of rare mantle nodules & gemstones (See Figure 2 in Gallery below) 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 marketing, these could capture parts of the colored gemstone market. For example, many Cape Emeralds are more beautiful than emerald.

What surprises me the most - Wyoming has one of the largest kimberlite-lamproite-diamond provinces in the world that extends south into Colorado. Montana has a separate province as does Kansas. A potential multi-billion dollar industry that the state's are ignoring.

References Cited

Coopersmith, H.G., Mitchell, R.H., and Hausel, W.D., 2003, Kimberlites and lamproites of Colorado and Wyoming, USA: Geological Survey of Canada, Ottawa, Ontario>

Hausel, W.D., 2014, A Guide to Gemstones, Gold, Minerals and Rocks: GemHunter Books, 368 p. 

Hausel, W.D., 2006, Geology and Geochemistry of the Leucite Hills volcanic field, WGS report of Investigations 

Hausel, W.D., and Sutherland, W.M., 2006, World Gemstones: Geology, Mineralogy, Gemology & Exploration: WSGS Mineral Report MR06-1, 363 p.

Erlich, E.I., and Hausel, W.D., 2002, Diamond Deposits - Origin, Exploration and History of Discovery. Society of SME. 374 p.

Hausel, W.D., McCallum, M.E., and Woodzick, T.L., 1979, Exploration for diamond-bearing kimberlite in Colorado and Wyoming: an evaluation of exploration techniques: Geological Survey of Wyoming Report of Investigations 19, 29 p.

Hausel, W.D., Glahn, P.R., and Woodzick, T.L., 1981, Geological and geophysical investigations of kimberlites in the Laramie Range of southeastern Wyoming: Geological Survey of Wyoming Preliminary Report 18, 13 p., 2 plates (scale 1:24,000).

Hausel, W.D., Gregory, R.W., Motten, R.H., and Sutherland, W.M., 2003, Geology of the Iron Mountain Kimberlite District & Nearby Kimberlitic Indicator Mineral Anomalies in Southeastern Wyoming: Wyoming State Geological Survey Report of Investigations 54, 42 p.

Hausel, W.D., 1998, Diamonds & Mantle Source Rocks in the Wyoming Craton with Discussions of Other US Occurrences. WSGS Report of Investigations 53, 93 p.

Hausel, W.D., 2009, Gems, Minerals and Rocks of Wyoming. A Guide for Rock Hounds, Prospectors & Collectors. Booksurge, 175 p.

DIAMOND PROSPECTING HINTS When you decide to prospect for diamonds, learn to recognize diamond and then watch your gold pan to see if you trap any of these gems. Diamond has a specific gravity of 3.5, and will concentrate with black sands in a gold pan. So when you are panning and you see a transparent to white crystal (or even better - a pink or blue crystal) in your pan in the middle of the black sands with distinct greasy luster. Take it out and look it over closely with your hand lens (magnifying lens). It should look as if it has a thin coating of grease on the surface.

Now get out your diamond detector and test the crystal. Diamonds have unique surface conductivity, which is why they feel cool to the touch of your lips (ice), and can be detected by a diamond detector. All you have to do is switch on your diamond detector and touch the suspected diamond with the probe. If it reads "diamond", be sure to send it to me as a gift. If it reads "simulate" it is something other than diamond and don't bother sending it. Diamond detectors are so easy to operate that with some effort you can even teach a monkey and rarely a politician how to use them. To aid in your expertise in diamond hunting, buy a few very cheap, uncut, rough diamonds to have in your personal collection for comparison and to assist in your mineralogy education.

Without mineralogical training or a diamond tester, you probably will not be 100% positive as to you have. So take your crystal to a pawn shop and ask for $1 million - the pawn broker will most likely be able to tell you if you are crazy or if you have something of value. But also remember rough diamonds are not worth much unless you have a large one (10 or more carats). Remember those bozos on Gold Rush in South America when all they could find were diamonds - it took some time, but I suspect they finally caught on - small rough diamonds just don't have much value - if you have a good-quality rough gem diamond of about 1 carat - you may be able to get US$100 or $200 for it. If it is industrial diamond, you might be able to get enough to by one can of soup. Faceted diamonds attached to a gold necklace in a jewelry store do have value. And BIG gem-quality diamonds of a few hundred carats can be traded for a good field vehicle - such as a 4-wheel drive Porsche with monster tires.

Now examine photos of raw diamonds and check my sites on diamonds - I have a few of them scattered all over the internet. Now search the internet for photos of rough diamonds. Look at the crystal shape of the mineral in question - most diamonds look equal-dimensional (a few will not) and are isometric. Look for trigons on the crystal surface. 

Now this is very important! Don't let your imagination run wild. I've had hundreds of people report they see trigons (little triangles on the crystal surface) when there was nothing there. Not sure what they were smoking, but it should be easy to tell if you have triangles on a crystal surface or not. The crystal habit can also be helpful. Many rough diamonds occur as octahedrons - crystals that look like two pyramids attached at their base - 8-sided crystals. But again hold on - don't run out a buy a new car yet unless you plan to send it to me. There are many other minerals that form octahedrons, so this in not diagnostic. Another common crystal habit is a macle - looks kind of like a flattened triangle. Then there are cubes - those 6-sided crystals that look like dice. But then there are many modifications of these crystal habits.

Many placer diamonds have been found in California and Colorado in the past, and other diamonds have been identified in many States across the nation. It is likely hundreds of rough diamonds were also discarded by gold prospectors not knowing what diamonds looked like and others likely are in private rock hound collections waiting for someone to discover the gemstone. 

To begin a search for diamonds, focus on kimberlites in cratons. Cratons are very old continental cores. In the past (2009), I published two articles for prospectors on how to use a Personal Computer to find cryptovolcanic structures. I recommend reading these articles as they will give you an advantage over other prospectors. First start searching areas where kimberlites have already been reported because kimberlites often occur in clusters. As you begin your search, start identifying known kimberlites and pinning them on Google Earth to provide you with a visual reference. Now start looking for alignments (lineaments) of kimberlites as kimberlites also occur along deep-seated fractures. When you identify a fracture (lineament) with a kimberlite along the fracture - project that fracture out a few miles  and look for evidence of other kimberlites along trend. 

As an example, search for the Sloan 5 kimberlite in Colorado on Google Earth at the following coordinates: 40°52'6.17"N; 105°26'52.54"W. Here is a roughly elliptical open park free of trees that is about 0.12 miles across in a north-south direction and maybe 0.06 mile in the east-west direction. This park marks the kimberlite pipe. The fact that it is elongated in the north-south direction suggests this could be the location of its primary fracture. As you look in this area, you will likely see other lineaments and open parks, all worth exploring. 

Now lets look at the Indian Guide district in Wyoming west of Chugwater. I found these anomalies many years ago, but these remain unexplored and unsampled. Are they just ponds or are they kimberlites? Check the Indian Guide photo in the gallery above. This is a false-color infrared image over Indian Guide showing a group of depressions some which have small ponds (water shows up as black in this image). All of these are structurally controlled (note all of the lines (lineaments) that project through the various depressions). Note that a couple of ponds also have white rings (kind of like the bathtub rings we use to leave as kids for our mothers to clean up). On the ground, these react to weak (10%) hydrochloric acid. There is no known source for calcium carbonate in these Precambrian rocks that we know of, so these may be kimberlites.

If you were to visit these on the ground, you would want to look for rounded bounders and cobbles in the depressions (characteristic of kimberlite), and look for blue ground clays with considerable calcium carbonate as well as look for the kimberlitic indicator minerals and even diamonds. So how many kimberlites (or cryptovolcanic depressions) can you find in this one photo? At least 25. Keep in mind that when blue ground and yellow ground kimberlite was first discovered in the Kimberly region of South Africa, people though they were finding diamonds in an old paleoplacer because it contained many rounded boulders, cobbles and pebbles. However, instead of being rounded by stream action, these were rounded by magma polishing as the material was carried to the surface in the kimberlite magma. The kimberlite host rock was later identified as the early diamond prospectors dug deeper into the yellow ground, then blue ground and finally the kimberlite.

Next, learn to recognize the classical kimberlitic indicator minerals as these have been found in many places in Colorado, Montana and Wyoming. and even in places like Kansas, California and Michigan. You can search for kimberlitic indicator minerals by panning streams or in the questionable crypto volcanic depression. 

When you find kimberlitic indicator minerals in streams, it is assumed they originated from a short distance either upslope or upstream. For example, chromian diopside will only transport 0.25 to 0.5 miles from a source kimberlite. Pyrope garnet may transport 1 to 2 miles from the kimberlite and picroilmenite only 1.5 to 3 miles from the kimberlite. Several years ago, we conducted a stream sediment sample survey in southeastern Wyoming searching for the kimberlitic indicator minerals by panning various streams and we identified more than 300 anomalies. The source of most of those anomalies remains unknown.

Over years of looking for kimberlite and lamproite, I was amazed at how people overlook these rocks and many gemstones. On one field trip, I led a group of 50 geologists & prospectors to the Chicken Park kimberlites in Colorado. I told the group I would walk them over kimberlites and they were to watch and let me know when they saw kimberlite. I walked them over kimberlite a few times and not one person saw them until I took them back to show them what they had missed and the Chicken Park kimberlites are some of the more obvious kimberlites in the area. So you as a prospector have an opportunity to find a major diamond deposit. Here's how to find the obvious pipes:

Fly your Google Earth or Virtual Earth to the Kimberly Region of South Africa. Look for some diamond mines - now look in the areas surrounding the diamond mines (I found several probable kimberlites in this area). Do the same for the NW Territories of Canada (search the Ekati mine). The Ekati has about 120 kimberites in the area surrounding the mine, most are under shallow lakes.

COPPER Minerals, Ore and Gemstones

Book on minerals & rocks in Wyoming

“Iron is taken from the dust,

And copper is smelted from rock.

“Man puts an end to darkness,

And to the farthest limit he searches out

The rock in gloom and deep shadow.

“He sinks a shaft far from habitation,

Forgotten by the foot;

They hang and swing to and fro far from men.

“The earth, from it comes food,

And underneath it is turned up as fire.

“Its rocks are the source of sapphires,

And its dust contains gold.

“The path no bird of prey knows,

Nor has the falcon’s eye caught sight of it.

“The proud beasts have not trodden it,

Nor has the fierce lion passed over it.

“He puts his hand on the flint;

He overturns the mountains at the base.

“He hews out channels through the rocks,

And his eye sees anything precious." 

- Job 28:2-10

Books on mineralogy, and copper deposits, itled me to the conclusion there are many copper deposits with dozens upon dozens of cupriferous minerals and cupriferous ores. The one thing about the many copper minerals found in the world is that many are brightly colored making identification a lot easier for the prospector and geologist. And, if you are looking for other types of ore - such as gold, silver, platinum group metals, lead, zinc, molybdenum and many others, copper is more abundant and usually mobilized with other important metals during pyrometamorphism and hydrothermal activity. This means when metals are put into motion by heat, pressure, and fluids, they seem to bunch together and become trapped near the earth's surface in structures, or by chemically favorable rocks. So, when you see copper, be sure you look for other nearby valuables.

In the West, copper is not unique: and you will find in all over the hills in old mining districts in Alaska, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, South Dakota, Oregon, Utah, Washington, Wyoming. You can spend a lifetime trying to collect all of the copper minerals, but when you get close, someone will identify a new one that was previously unknown.  But the West is not unique, as many copper deposits have been found across Canada, Mexico as well as throughout the United States. In some places, there is such much copper, one could decorate a house or even a town with all of the copper. And for a lot of people, its hard to imagine so much copper and other metals and gemstones can be sitting right on the surface and much of it untouched and overlooked by others. 

Massive chalcopyrite (copper sulfide) from the
Ferris-Haggarty mine, Wyoming

Some copper minerals are used as semi-precious gemstones, but many are soft and must be protected. Others produce spectacular collector specimens, decorative stones and lapidary. There are so many copper minerals that when I was in graduate school, one of my office mates built a reputation and PhD dissertation on identifying previously undocumented copper minerals. There are a few copper minerals that are more commonly used in gemstones and lapidary and these include turquoise, chrysocolla, malachite, azurite, native copper and cuprite. 

In many of the Western States, the more one searches the mountain sides, the more copper minerals they will find, but in the copper state of Arizona - copper is literally everywhere! You will find it in the hills, basins, people's back and front yards and even in parking lots. The photo in the upper left is a boulder of azurite (blue), tenorite (black), dark red (cuprite) and minor malachite (green) from the Morenci, Arizona district. Imagine wearing that boulder as a pendant around your neck.

Gossaniferous (limontite, goethite) matrix with vugs filled

with azurite (copper carbonate), Absaroka Mountains,

Wyoming.

Although azurite (H=3.5 to 4), malachite (H=3.5 to 4), chrysolla (H=2.5 to 3.5) and tenorite (H=3 to 4) can produce extraordinarily specimens due to vivid color combinations, having a soft hardness precludes much use of these as gems because they are so easily scratched. Thus these and other soft copper minerals must be protected. Others such as turquoise (H=5 to 7) are more favorable for wear. Then there are the extremely colorful minerals such as covellite (H=1.5 to 2) and bornite (H=3 to 3.25) (also known as Peacock copper) that are unmatched in nature.

10% dilute HCl is used
extensively by geologists
to (1) tell if a rock or
mineral has carbonate.
and (2) reduce metallic
sulfides, oxides, carbonates
etc. to naive copper on
weathered rock hammers

HOW TO IDENTIFY COPPER MINERALS

One distinct characteristic of copper minerals is a reaction to dilute (10%) hydrochloric acid. Copper carbonates such as azurite and malachite will fizz when they a few drops of hydrochloric (muriatic) acid are dropped on them; and most copper minerals will replace rusted iron with native copper when the copper is wetted with hydrochloric acid. Geologists pack around old beat up rock hammers and place a few drops of weak hydrochloric acid on a mineral suspected to contain copper. Next they rub their rock hammers in the wetted mineral. After it turns to mud on the rock hammer, they clean off the mud with their fingers, and if the mineral contains copper, rusty scratches in the rock hammer will be replaced by native copper.