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DAS Meteor Presentation

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#1 csrlice12

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Posted 14 June 2014 - 07:20 PM

Attended the Denver Astro Society monthly meeting and the presentation was by two of our local experts on Meteors. It was a very interesting presentation to include fragments of the moon and of Mars. there were plenty of other meteorites to view too, one cut from the meteor from the Arizona Meteor Crater (apparently he// to cut as it contains nanodiamonds). All in all, a very interesting night...after the presentation, many went to Chamberlin Obsevatory.

#2 meteordealer

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Posted 17 June 2014 - 03:06 PM

I agree with their assessment of cutting Canyon Diablo meteorites. I have a horizontal bandsaw with a hydraulic feed system that i use for iron meteorites and even then CD's are a bear to cut. I've also found Muonionalusta to be difficult.

#3 lee14

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Posted 17 June 2014 - 09:05 PM

Canyon Diablos are high in carbon, which often manifests as graphite. If the nanodiamonds weren't already present before impact, the extreme pressures at breakup certainly could have converted some of that to the diamond form. We know the impact was particularly violent because there is virtually no intact iron at Barringer, the only remnants surviving at nearby Canyon Diablo.
The most effective way to cut CD's is with more diamonds. There are grit edged bandsaw blades available, but they're fairly expensive, and if one breaks prematurely due to metal fatigue, you're out a couple of hundred bucks. I like a grit edged lapidary blade myself, with a gravity feed. It's a little slower, but a good quality blade will last quite a while and is far more cost effective.

Lee

#4 peter scherff

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Posted 18 June 2014 - 06:45 AM

Hi,

Not all the diamonds in Canyon Diablo are nano-diamonds. Here is one that had to be cut around:

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#5 meteordealer

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Posted 18 June 2014 - 11:04 AM

I use large diamond bandsaw blades. When they break, i just solder them back together with a high grade silver solder. I can essentially run the same blade until all of the diamond grit has worn off. That makes them more cost effective.

For most irons, a good bimetal blade with a low tooth count is sufficient.

#6 lee14

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Posted 19 June 2014 - 08:58 AM

Interesting. I've never considered silver soldering my horizontal bandsaw blades, I figured they'd be under too much tension for a non-welded joint to hold up. I routinely rejoin wood cutting blades for the vertical bandsaw, and I will certainly try this on the meteorite cutting blades. Thanks for the suggestion!

Lee

#7 lee14

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Posted 19 June 2014 - 09:30 AM

Challenging as they are to cut, that's what I like about Canyon Diablos, you never know what you're going to find. I've found entirely muted Widmanstatten patterns, gorgeous troilite or graphite inclusions, and W patterns that had been twisted by the break-up but were still recognizable. Sometimes I skip the etch entirely and just go for the polished look, like this 14 gram piece

Lee

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#8 meteordealer

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Posted 20 June 2014 - 10:26 AM

I've never had much luck getting a good widmanstatten pattern out of Canyon Diablo's. I usually end up with highly shocked individuals.

This is a 12 pound individual that i cut in half a few months back. One half of the cut face displays a nice widmanstatten pattern, the other half is highly included with a muddy, shocked pattern.

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#9 lee14

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Posted 20 June 2014 - 08:48 PM

I've encountered a range of Diablos, some are heavily shocked like yours,
some have a perfect Widmanstatten pattern, and some are altered, with
the pattern still present.
This one was deeply etched in an attempt to
pull out a pattern, but it just wasn't there.
Except for the bright bands, the surface
of this 66g piece was quite grainy.

Lee

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#10 lee14

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Posted 20 June 2014 - 08:51 PM

About half of the ones I cut turn up what I consider an ideal pattern for Diablos.
This is a 53g end cut.

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#11 lee14

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Posted 20 June 2014 - 09:03 PM

This 161g end cut is the only one I've seen to exhibit
an altered pattern that wasn't muted, just curved.

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#12 Dave M

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Posted 22 June 2014 - 06:25 AM

Thats a cool Canyon Diablo specimen with the diamond in it.






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