Nuking And Boiling Fossils In Water

[Bev]

Front side of the rocks selected.

Back side of the rocks selected.

Sorry for the poor pictures but when I step outside from a 72 degree air conditioned house the lens on the camera is immediately fogging. Current heat index is 95 degrees.

Okay, so here we go!

It took about 12 minutes for the water to come to a rolling boil. I set the timer for 20 minutes. Will have pics of the pot of rocks after they come out.

Here is a picture of the pick I am using. But I might just go for the engraver too.

I scratched all of the rocks with the pick and tried to break them all with my hands - no go.

I also have a rock in the freezer after reading Northstar's success with the blastoid.

Note of interest: After the rocks sat overnight and came to room temperature they rehardened. But the softer matrix was still much more pliable. So I think that working with them hot is a good idea. Which makes me think that I shouldn't be boiling all at the same time.

And Bob is making fun of me and my stone soup! "Smelling good Dear!" "Nice thick broth."

Edited September 4, 2013 by Bev

[Ramo]

Bev, Thanks for taking the time to photograph your methods to show us.

Ramo

(PS Marco likes to boil stuff in acid in his spare time. If he thinks something is too dangerous, I think I'm inclined to listen to him.)

[Bev]

Pot of rocks on the stove. Brought to a boil and then boiled for 20 minutes. HOT!

This was a qualified success. I popped off several surface fossils (a brach and a crinoid link) easily.

But the more deeply embedded gastropod would take more work, note point of pick. This rock had an acid dip before I ever started this experiment and I think that hardens the matrix.

TOTAL SUCCESS! Stewartville member of the Galena Formation. Ceph was out within 5 seconds!

Tentative failures. But they were also cooling significantly as I was working. Slightly easier to scratch.

Success! Broke with just hand pressure. Split with pick. Lifted several off the plate and undid several brachs piled on other brachs.

Personal Conclusion

I think the microwave does something additional to the rocks beyond boiling.

Boiling:

Crumbly limestone it works excellent with - makes sense.

Hash plates that are cemented only with clay or sand or just the shells are successfully broken with this technique.

If a fossil is lying on top of limestone matrix this works and may help embedded fossils release with an engraver.

Do it while their hot.

Once they cool most return to their normal hardness.

Freeze and quick thaw to be done yet.

I consider this another tool in the prepping arsenal. Just one more thing you can try. :-D

Edited August 26, 2013 by Bev

[Bev]

Resounding Success!

Here I froze this rock then dropped it into already boiling water.

Front and Back of the Rock before Experiment.

After boiling for about 10 minutes, I dumped it out of the pot and

immediately took it to the work bench to see if I could dig anything out of it.

I was able to get many more small pieces, even embedded ones out of this rock.

It also seemed to fracture very easily with just a tap of the hammer.

Here is a cross section of the rock. Very dense.

Also, it seemed to me that the fossils were very clean and more clear than before!

As many times as I have examined this rock,

I never saw the second trilobite pygidium until the rapid freeze and thaw.

[Bev]

Here is the broken part of the rock with the trilobite pygidium in it.

Here it is upclose.

Freeze and rapid thaw.

So, I am very pleased with this technique so far.

[bdevey]

I have nuked before, but beware water expands to steam at 1600 times. [if i'm correct] ....... Only 2.5 cu millimeters of water hidden in the rock, will explode to 400 cu centimeters of steam. That would be a very strong blast in the kitchen.

[Bev]

Limestone rock and fossil.

Soaked it overnight in room temperature water.

Froze it in the freezer for 12 hours.

Put a pot of water on to boil.

Dropped the fossilized rock into the water at a full rolling boil and let boil for 20 minutes.

Drained the water out of the pot and picked the rock up with a hot pad and took it to the garage.

I rapped it twice with a common construction hammer (smooth head) and out the fossil popped!

SUCCESS!

Afterthoughts...

Nothing happened to this fossil except perfect extraction from the matrix,

but with future extractions I plan on putting duck tape over the fossil before rapping the stone.

1. I have lousy aim!

2. If the fossil should fractor all of the pieces would be there.

Yeah Bev!

[Fossildude19]

freeze 2.jpg

Limestone rock and fossil.

Bev,

Just a question - had you previously tried to whack the rock before the test?

Just wondering what you're using as a control for the experiment.

It looks like from the first pic, that you could probably extract that gastropod without much work to begin with.

Regards,

[Scylla]

The problem with nuking the rock with water is that the microwave can easily get the water supercritical since it inputs energy into the water molecules faster than it can dissipate. Now having a rock in there will actually help as it will act as a boiling chip and help the boiling process. However as several people have pointed out or implied a steam explosion could ruin your day. I suspect the reason this is working is that the steam is forming in small voids in the rock along the fossil and helping to separate it from the matrix. If you are going to continue doing this, let the nuked rock sit for a few minutes after the microwave stops and leave the room while it is running. I think the harder the rock, the bigger the explosion you risk.

[Bev]

I'm not nuking the rocks anymore. Sounds dangerous.

Just freeze and thaw.

And the last one, yes, I did whack it a couple of times before I tried the freeze and thaw technique. It seemed to produce a crack alongside the fossil, but was just a no go. That crack seemed to enlarge during the freeze/thaw process.

Hey guys, this is definitely a tool in my prepping arsenal now! No cost. Low tech. It works. :-D

[lmacfadden]

Very interesting experiment Bev - thanks for taking the time to document it and share it with us. I'll stay away from the microwave oven, however, the freeze and thaw method is brilliant.

[Wrangellian]

If you do use the nuker, I don't think it is necessary to freeze it as well, considering that, with the freeze-thaw method, it's the freezing part that pushes the rock apart, not the thaw. Of course putting a wet rock into the nuker will produce steam which will have the same results (if more violently!).

When I attended that nuker demonstration there were occasionally explosions but never anything that would blow apart the nuker and never in hand (I think they waited a bit before taking it out of the oven). Also, if I recall, part of the process involved putting a hot (dry) concretion out of the nuker and into a bucket of water.

As I said before though, I never thought this method was safe to the fossil, never mind me - I just don't care to do any more jigsaw puzzles! Maybe it is better for your hash pieces than a delicate ammonite, though.

[Wrangellian]

BTW if you're not having much luck with the freeze/thaw, try longer soaks and longer freezes. Just a thought

[Bev]

When I have nuked rocks it was rocks in water, never a dry rock or a dry frozen rock. Might make a difference. And as pointed out, I have limited matrix - limestone exclusively or packed brachs.

This is a technique that I will definitely continue to perfect.

[Wrangellian]

I think when the demonstrators nuked 'dry' concretions, they were either soaked and then put in the nuker (ie. not nuked in a glass of water), or simply put in as-is counting on the presence of small amounts of water in the fine cracks of the concretion which of course, either way, would turn to steam and expand. I don't remember the exact steps employed but I do seem to recall them putting the rocks into a bucket of water after nuking, and probably repeating the process if they didn't break apart the first time, and of course they would pick up more h2o after each dunk. I'll have to dig out the paper describing this and let you know.

[ecleland]

Try the pan boiling method and tell us how it goes, but I've been trying to find a way to clean my shell fossils for a long time this might be it!

[Bev]

Try the pan boiling method and tell us how it goes, but I've been trying to find a way to clean my shell fossils for a long time this might be it!

If your shells are small, try the ultrasonic cleaning method. I think it works GREAT!

[PennyT.]

Be careful and I'd have another microwave for a backup, ha ha!