Coaldale Crater Gemstones, Meteorite Impact Produces Rare Specimens Options

[ASTROBLEME]

Members and Guests of Colorado Prospector,

Many years ago I discovered a highly eroded, geologically complex and very ancient impact crater centered 3 ¼ miles northwest of Coaldale, Colorado (USA). I am announcing this discovery as a long-time contributor to this forum in an effort to assure that the public has access to this information. Dan (the owner and operator of Colorado Prospector) is preparing some of my "Coaldale Crater" specimens for jewelry settings. He has graciously agreed to document his work progress so that others can gain a better understanding of the effort it takes to transform these raw materials into valuable gemstones. Please take time to follow this project along the way. I hope you find the subject interesting.

I'll be sharing the science behind this amazing discovery as our work progresses. This research builds upon my work at Gunnison Crater, Westcliffe Crater, Silver Cliff Crater and Hillside Crater that proved an extension to the 38th Parallel Crater Chain dating to the Late Devonian Period. Although the Coaldale Crater is also along the 38th Parallel, it is not part of the well documented crater chain system. My efforts in the Coaldale Colorado region included collecting field survey data, acquiring and analyzing numerous geologic specimens followed by an extensive review of the relevant scientific literature. The results support an impact event that occurred during the Oligocene Epoch.

For now, I'm providing the attached map depicting the present peak ring exposure. It is fascinating that this impact crater has survived the deep erosion and strong fault deformation that Mother Nature has provided continually over the past 27+ million years.

Sincerely,

ASTROBLEME

[CP]

Very cool information Johnny and thank you very much for posting your discovery announcement via the forums here! We will be looking forward to more updates on your work through the years to prove up this craters existence too, just fascinating! Obviously since that killer gem piece was found by your dad years ago..... (GOTTA' SAY WHOA AND WOW TO THAT! ).....that is a sweet rock! So that would be a "chondrite" nodule? If I'm understanding it right?

You've had an interest in meteorites, craters and mining in general since a very young age. Bet you've had a lot of time vested in research and a whole heap of info to go with it over the years. Going to be fun watching this thread and project progress for sure! Stay tuned folks if you like this kinda' science stuff.

I'd also like to take one moment to mention that Johnny here happens to be our longest running yearly club member thus far. That says a lot to me and the rest of the club I think it is worth a mention. Thank you Johnny!

So, Johnny and his wife Donna drove down to bring some samples/pieces to cut for this project. I'm very pleased and proud to work some more material for Johnny on this project and it was great to finally get to meet them both after all this time too! We had a great visit and they brought several samples to work with for this project as well as a couple other samples I'll also be making projects out of later....... Those are not from this crater or included here though.

For now I'll be working on a cut lot of the Carbondale Crater Meteorite sample provided and tektite samples provided. The one meteorite sample we'll begin with for the cuts. First is a pic of the rough meteorite sample.






Since this is also a project to help the further study of this material, I also took some extra time before cutting to brush clean out the saw used. So after cleaning out any other material/dust from previous cuts in the water box area under the saw, I cut the meteorite first which produced these cuts in the pic below....... The idea behind the pre-cleaning of the water box container was to reclaim what the saw cuts out of the meteorite sample....ie small chondrite nodules. So in the small bag lower right is the reclaimed saw cuttings for Johnny's further study purposes as well as two very thin slices middle right and upper right also for study purposes. One is about 1 mm thick the other approx. 2 mm. and that is done free handed on a small saw with a thick/stiff blade. Other cutters may have used a thinner more flexible blade for less loss during cutting, but I feel the opposite with that thought for anything over 3/8" thick....I think a flexible blade causes more waste actually with the uneven cutting that occurs (especially trying to slice or slab) which then must be ground flat anyway. All these pieces are flat enough to be blank fronts of the stones to be cut, or back sides without further grinding or waste of material. More consistent cuts equal no waste!

All the other nine pieces in this pic could be used to cut a stone I think, time will tell, the meteorite sample was solid and cut well! The lower left piece was part of the original surface that Johnny hand polished previously and shows how the finish cut/polish will look darker than the slices cut now do.







There are several (a bunch) tektite samples provide to work with of which I sorted into 4 types so to speak...... Unfortunately all the tektite material is highly prone to cracking and with some effort through several samples I did manage to get a few workable slices. The types of material are all represented in this pic of rough samples. A conglomerate (upper right), a very light green(upper left), a range of medium greens (lower right and center), and a few very dark green with white banding (lower left).







After cutting I've culled out these pieces as possible to work......the conglomerate had the worst fracture problem and there is only 1 viable slice so far for that (lower right with 3 thin study slices), next worst with the fracturing was the lightest green material (upper right) which may not stay together well enough to endure cutting/cabbing process. The middle row (up/down) is of the darkest green with white banding, I think it will cut nicely but still a fracture concern, top piece of that row shows rough side, with two under showing cut sides and one thin study slice at the bottom of that row. Far left group is of the medium green types and showed best for less fracturing but still does have them. Top piece shows a rough side, the rest show cuts and of course one thin slice at the bottom for study purposes. These have many inclusions that should be very pretty when polished out to finish.




More updates to follow folks, this is going to be a fun thread and project!