The Complete Gekko Rocks Collection

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The QCC
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Joined: Sat Oct 11, 2014 10:13 pm

The Complete Gekko Rocks Collection

#1 Post by The QCC » Fri Aug 28, 2015 11:34 pm

Posted as one link to the thin section photos of the rock samples sent to me by forum member Gekko. Thus the name The Gekko Rocks.
The thin sections were made "by hand" using a QEP 60089Q 7" portable table saw, a HiTech Diamond 6" flat lap machine and many discs of silicon carbide sanding paper.

It is a two stage process making the thin sections.
In Stage one, the rocks are cut to produce two slices. The second slice is a backup if I mess up the first one. And it happened.
One side of the slice is ground and polished flat and cemented to a petrology slide using Epoxy 330.

Stage two the mounted slice is ground down to approx. .150 mm using 100, 180 , 300 and 600 grit diamond flat lap wheels.
The slice is then polished with KEEN sticky 600, 1200 and 1500 grit silicon carbide sanding discs stuck to a flat lap backing disc.
The final polish is with 1 micron diamond paste on a microfiber cloth.
With luck, I can get the slice thickness down to a shiny 90-50 microns.

Many, many thanks go to Gekko for giving me the rock samples.
Some of the thin sections photos are quite nice and will make very nice gallery prints.
Thank you Gekko.

Please click on the photo to view The Complete Gekko Rocks Collection.
The Complete Gekko Rocks Collection
The Complete Gekko Rocks Collection
GekkoRocksIndexImage.jpg (56.43 KiB) Viewed 2138 times
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billbillt
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Re: The Complete Gekko Rocks Collection

#2 Post by billbillt » Sat Aug 29, 2015 5:05 am

I think you did a wonderful job with these...

BillT

Naphthalene
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Location: Moscow, Russia

Re: The Complete Gekko Rocks Collection

#3 Post by Naphthalene » Sat Aug 29, 2015 7:34 am

Consolidated efforts to produce those great images! Awesome views !
Thank you for sharing, The QCC.

I think "Arfvedsonite Pegmatite" series is my favorite amonge these presentations :)

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gekko
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Location: Durham, NC, USA.

Re: The Complete Gekko Rocks Collection

#4 Post by gekko » Sat Aug 29, 2015 8:06 am

Many thanks to The QCC for the excellent job you've done with them. Beautiful work. The variety of colors and shapes are wonderful.

The QCC
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Re: The Complete Gekko Rocks Collection

#5 Post by The QCC » Sat Aug 29, 2015 11:15 am

Thank you.

It was both frustrating and fun making the thin sections.
Around the 5th rock I felt "I think I've got it!".

Thanks for all the great comments.

mes0
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Location: Calgary, AB, Canada

Re: The Complete Gekko Rocks Collection

#6 Post by mes0 » Sat Aug 29, 2015 4:09 pm

oh man thin section sample prep has got to be one of the most time consuming processes... :) you really get an appreciation after doing a few.

The photos look pretty good.

Why the different exposure times?
The plain polarized light photos are always the clearest to me but also have the lowest exposure time.
Shopping for a nice Scope.

-Currently have monocular olympus students scope.

The QCC
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Re: The Complete Gekko Rocks Collection

#7 Post by The QCC » Sat Aug 29, 2015 4:44 pm

mes0:

The Canon 5D MkII controls the exposure times. The times vary according to the density of the area I drag the exposure window over.
If the field of view contains both very light and dark areas I will drag the exposure window over the area I am most interested in.
I leave the lamp brightness control at maximum so I do not have to set the white point every time I adjust the light level. The camera ISO is set to 400 and I shoot all photos as RAW. This gives me great latitude when making adjustments in Lightroom.

Yes, the PPL images appear sharper and lighter. Due to having one less piece of polarizing glass and more light in the exposure path
Plus I may not have the slice at a perfect uniform "thinness" resulting in cross polarized images looking less sharp than professionally made thin sections.

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gekko
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Re: The Complete Gekko Rocks Collection

#8 Post by gekko » Sat Aug 29, 2015 6:34 pm

The QCC wrote:Around the 5th rock I felt "I think I've got it!".
Yet even the ones that you made before you "got it" were excellent! I'm amazed at how quickly you made the sections, let alone photograph them under the various conditions. Again, thank you for all the work, but I think the results justify it.

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