A Series Of Unfortunate Experiments On Fracking Fossiliferous Rock

[mikecable]

This series of unfortunate experiments may well turn into some fortuitous knowledge. Maybe.

Unfortunate in that I acted likea sixth grade scientist when I started these experiments. No protocols whatsoever--I just went wild.

I should be starting this thread with a picture of a rock.

But I wasn't sure where the rock came from in the first place, and then I messed with the rock. And messed with the rock some more.

But I should at least end this post with some picture of the rock.

Best I can do tonight. Tomorrow will come the story of the unfortunate rock. Which does appear to be very fossiliferous.

[JohnJ]

Mike, what is the geology or general location of its origin?

[mikecable]

Mike, what is the geology or general location of its origin?

That's the first unfortunate part. I'm not sure. My brother gave it to me from one of my father's rock piles. It probably came from within 100 miles of Abilene, TX--most likely to the south or west. My best wild guess would be somewhere between Brownwood and Goldthwaite.

The next unfortunate experiment occurred in my lab at school. I put the entire specimen in a large beaker and submerged it in 5% household vinegar. Much bubbling and foaming ensued, which confirmed my suspicion that the matrix was limestone. After letting it soak for about an hour, I took it out and rinsed it.

That's when I realized I needed to slow down and think. The larger bivalve at the lower left used to have a pinkish, translucent coating that I wrongly assumed was silicate. It must have been calcified instead, because the vinegar had eaten it away.

[Missourian]

The larger bivalve at the lower left used to have a pinkish, translucent coating that I wrongly assumed was silicate. It must have been calcified instead, because the vinegar had eaten it away.

To check for silica, try scratching glass with it.

(I wouldn't recommend using the fine stemware. )

[mikecable]

To check for silica, try scratching glass with it.

(I wouldn't recommend using the fine stemware. )

You're right--I could have done a basic Moh's scale test. I just got excited and jumped ahead--exactly what I get after my students for doing. Now I'm boiling the matrix--but it's breaking down very slowly. I'm about to try a combination of freezing and boiling. Next will be hydrogen peroxide.

[Missourian]

You're right--I could have done a basic Moh's scale test. I just got excited and jumped ahead--exactly what I get after my students for doing. Now I'm boiling the matrix--but it's breaking down very slowly. I'm about to try a combination of freezing and boiling. Next will be hydrogen peroxide.

I'll be interested in your results. I have a number of unprepared fossils sitting in the basement.....

[xonenine]

I applaud your efforts Mike.A little unsure how to proceed myself, I soaked several likely looking Silurian hash plates in household vinegar.The bubbling was very slow, but steady for several hours.At the end the hash showed alot more detail, and quite a bit of unexpected color, and the most minor signs it was starting to affect the fossils as well - several more hours, and the vinegar had stopped bubbling.

the fossils had at that point lost a discernible amount of detail, and I will now try other solutions for this matrix, which is to say, the vinegar may yet prove useful for other samples, I havent tried rock from several other locales yet...

I imagine if I only wanted to clean this hash, a half hour would more than suffice, and I will clean a few more pieces, the smaller one I pulled out after 1 hour turned out nicely...

a photo after about 2 hours in the vinegar...

[xonenine]

here's a piece of the same matrix after a quick 15 minute bath, followed by scrubbing w/ a soft toothbrush.Next I''l get the Muriatic acid, which I'll try next... :)and a large crinoid stem (10"+) after a 1/2 hour soaking

although there wasn't noticable damage, I'd refrain from using the vinegar for any longer...

Edited December 18, 2011 by xonenine

[Mr.Scaphite]

Few methods I have read about not mentioned here is the use of peroxide solution, sodium hydroxide and lastly was the use of electric current. Yep, a professor I had in college did research on it, high voltage through wet matrix. Sounded dangerous to me. Tried to remove shark teeth from the Turner sandy member of the Carlisle shale by way zaping it... he he he.

[xonenine]

a bump for the ever popular PDF Liberation of Fossils Using High Voltage Electric Pulses

[Herb]

try some dishwasher liquid (Cascade) and a soft brush, it will help soften the clay/silt. And vinegar and a soft brush. Leaving it in the acid will destroy  the details.