Friday, December 7, 2012

Kimberlite Pipes and Volcanoes

Would you like to see a kimberlite pipe erupt? Me too! But don't stand too close. These types of eruptions are very explosive at the point of eruption, and likely have gaseous emplacement temperatures at the freezing point of water and velocities of Mach 3!!!

Below are some photos of kimberlites, diamonds, books, etc, that I wrote and photographed over the years (

High-wall with exposed diamond-bearing kimberlite breccia at the Kelsey Lake mine, Colorado. If you have Google Earth on your computer, search for 'Kelsey Lake, Colorado' to see the location of the blue ground to see this former diamond mine. Note the large angular rock fragments in the highwall - these indicate there was a tremendous amount of explosive energy during the eruption of this kimberlite pipe (photo by the author - Gem Hunter).
Diamond-bearing Schaffer kimberlite dike in Wyoming exposed in dozer trench in 1979 or 1980. Jay Roberts, geologist, stands in the trench for scale while I took this photo. The kimberlite is the gray-blue material. The reddish material in the foreground is sheared Proterozoic granite (Sherman granite facies).
Diamondiferous kimberlite from the Sloan 2 pipe in Colorado. Note the large, rounded pyrope garnet.  The Sloan kimberlites have identified diamond resources and remain mostly untouched. DiamonEx had acquired the Sloan property in 2007 under my direction, but the 2008 economic collapsed took its toll on world diamond prices, the company, and the world. The property was abandoned by DiamonEx, yet it likely still encloses hundreds of $millions in diamonds.
Kimberlite (Devonian) and Granite (1.4 billion years old) contact exposed 
by bull-dozer, Schaffer kimberlite complex, Wyoming. 
Note how sharp the kimberlite contact is and there is no
 evidence that the granite was baked.
Maxwell diamondiferous kimberlite in Colorado - one of many kimberlite pipes and dikes in Colorado and Wyoming that still remains untested for commercial diamonds. Diamonds were recovered from a small sample from this pipe (C.D. Mabarak, personal communication).
Buried kimberlite dike in Wyoming - the kimberlite underlies 
the dirt in the right half of the photo where there appears to be 
thicker and slightly higher vegetation.
Diamonds in the US?  From Diamonds and Mantle Source Rocks in the Wyoming Craton - by W. Dan Hausel, 1998. The diamond-shaped figures represent reported diamonds. The triangles are kimberlite localities (open triangles are diamond-bearing kimberlites), squares are high-pressure volcanics similar to kimberlite, + are lamprophyres and lamproites, the + enclosed by a diamond is diamond-bearing lamproite, the white diamond is the location of the Great 1872 Diamond Hoax site, the dots represent kimberlitic indicator mineral anomalies of note.
Close-up of diamond surface with some of the distinct trigons etched in the 
surface.  Don't know how to identify diamonds? Its not all that difficult. If 
you do not have a background in mineralogy, all you need is the 
Diamond Detectoryou can even make your own.
Popular book on diamonds in the US - you might be able to get this at the Wyoming 
Geological Survey at the University of Wyoming.
Book on rocks and minerals that also has brief information on diamonds and on 
kimberlite and lamproite. Available at Amazon
Another popular book on gemstones (and diamonds) that the Wyoming Geological Survey 
forgot to reprint after the current edition was sold out. Photo by Wayne Sutherland.
Gem kyanite from central Laramie Mountains (we found billions of 
carats of this gem - but it remains undeveloped). 
Some of this gem is found with iolite, ruby and sapphir
in the central Laramie Mountains.
Booklets on diamonds from the wyoming geological survey (photo by Wayne Sutherland).
Free pamphlet on diamonds - this may still 
available in Wyoming. 
Rough diamond from Wyoming - wow, aren't 
these stones beautiful! Note how the gem has kind of a 
greasy luster. This is characteristic of diamond.
Exploration methods for kimberlite - this was one of the first 
diamond publications I published. I was excited about t
he publication and the work I did. For me, this was the perfect 
job with imperfect wages. But what the heck, you can't 
have everything.
Recent publication on geology of the Leucite Hills lamproites and possibilities of diamonds in the Leucite Hills lamproites in Wyoming (may or may not be available at the Wyoming Geological Survey).  I loved  working in this area. While conducting research on diamonds, we recovered diamond-stability chromites from some of the lamproites (this suggests the chromites formed under pressures and temperatures similar to that of diamond formation; thus there is a possibility for diamonds in this region).

Essentially all of the projects at the Wyoming Geological Survey were so underfunded, its amazing we found anything. Even though these rocks may contained diamonds, we were unable to test any material (other than a couple of rocks). Elsewhere in the world, there is a correlation between olivine and diamond content in some lamproites, so I was excited to find a couple of anthills with considerable olivine in the northeastern portion of the Leucite Hills. After looking at some olivine with a hand lens, it was apparent nearly all was gem-quality. So I took the two anthills in sample bags - and Robert Gregory processed the material (no diamonds were found), but we recovered 13,000-carats of gem-quality peridot from this sample!

Diamonds in the world - a 374 page book, but price is too high 
(don't blame me, I received no royalties for this book 
and the publisher (SME) ignored all protests about the price).
Ruby from Granite Mountains, Wyoming. Specimen found by Eric Hausel.
Book  (42 pages) on a little known diamond-bearing kimberlite district in Wyoming. We didn't find any diamonds ( but found lots and lots of diamondbacks) - nor did we test any material for diamonds. However the geochemistry of all of the rocks showed that they all originated from the diamond-stability field and a couple of diamonds were reportedly found in the early 1980s by Cominco American.

Kimberlite 'diamond' Indicator minerals. These include pyrope garnet, spessartine garnet, pyrope-almandine garnet, emerald-green chromian diopside, picroilmenite (black metallic with white leucoxene crust) and two tiny black, octahedral chromites. Here is an example of how geologists miss gemstones. These were all recovered from the Sloan 2 kimberlite in Colorado when I was working for DiamonEx Ltd. Everyone working in this region for years focused only on the diamonds; yet these are all gemstones and can be faceted into beautiful colored gems while the chromites and picroilmenites could be fashioned into low-value gem cabochons.
Guide to finding gemsgold, diamonds and rocks in Wyoming 
available for free at the Wyoming Geological Survey.

There are many gemstones in Wyoming. Most people would have laughed if you told them in 1975 that Wyoming had the greatest variety of gemstones in the US. In 1975, Wyoming had known jade deposits and some agates - but that was about all.

Over three decades, the more I looked, the more I found: dozens of overlooked gemstone deposits and evidence for hundreds more which included commercial gold deposits along with more than 100 gold anomalies.  It was my intention to continue this research along with educating the public to help YOU find gemstones, diamonds and gold using methods I found successful in finding a few hundred mineral deposits.

But morally and ethically, I could no longer work for the Geological Survey or the State of Wyoming, so I moved on. Since 2006, there have been no discoveries of new metal or gemstone deposits.

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