Quenching Rock Experiment

[helens]

On the ID forum, Krystee found this really great rock that had a 'crackle' looking effect all over it. No one could quite ID the cause or whether it was natural or man-made.

There is a treating process called 'quenching', which essentially is heating a stone, then quickly plunging it in water. So I volunteered to try the process, since I have easy access to heat and water:P.

This doesn't mean that Krystee's rock was treated, we'd still like to know if others have found a natural rock out of the ground with this effect, so if you have found one (out of the ground yourself, if you bought it, how do you know it's not been treated?), please post there too, so we can settle this issue: forum.rocktumblinghobby.com/index.cgi?board=rocksidlib&action=display&thread=57417

My experiment started with these 3 stones that I thought would be fairly representative of jasper, agate, carnelian (if they aren't, let me know, I can't tell the difference :blush: ).



This is the result of 'quenching', without tracking time, temp, etc. Just a quick experiment:


Here's the longer process pix (give it a min to load, since there's a lot of pix).

First, Jasper. Before going in the flame. Ok, nm, IN the flame:


After 3 completely different heat/dip cycles (yes, it darkened and crackled). Seems structurally sound:


4th hit, dead on, since other 3 didn't explode rock in my face:


Final result of Jasper - crackled, color darkened, structurally intact:


Rock #2... agate (I THINK):


This one didn't even need water, it started crackling in the flame:


Not good... this after dipping and reheating - it broke in 1/2, and it started with no visible fractures:


Finally, carnelian (I think it's carnelian, may be an orangy yellow agate). Starts out smooth and clear internally:


After first heat dip - see the walls separating in the middle?:


This is better visible from the backside - BEFORE:


AFTER first dip - it's fracturing in the center:


After 3 dips, it's STEAMING still... this stone retains heat at the center, but wow... what a gorgeous crackle effect!!:


Another view. Now I dunked it in plain water... if I had dunked in dye, it would be REALLY pretty. As it is, you can really see the crackle backlit, but not so obvious from the front:


Final 3 effects (jasper changed colors, carnelian crackled beautifully, agate split in half and almost took out my eye)


The true test for how well it will hold up would be to cab the carnelian. If it crumbles, we know there's more to the process.

Keeping in mind that all I did was hit it with heat, no timing, no temp controls, I can EASILY see a controlled reaction in a kiln leading to a very effective treatment.

I wouldn't rule out that this could happen in nature... I mean a new lava flow can fall off into water for example. But, with certain stones, this seems viable.

When I get the chance, I'll cab the 2 intact pieces:).

[deb193redux]

I don't think these experiments hold out much promise of obtaining the almost cell-like structure in Krystee's slab.

I favor some sort of non-agate crystallization effect, or some sort of fossil cell effect, but really had no idea to offer Krystee. I think the fracturing from heating or quenching is always going to be much more random and not cell-like.

[helens]

Daniel, maybe my pictures weren't very clear... the 'carnelian' (IS it a carnelian??) is very cell like... the photo isn't very clear of it, but to the eye, it looks like the 'dragon skin' agate that's sold in jewelry.

Keeping in mind that I hit it with a torch, which is not even heating, and done quickly just to see the reaction, the portions not directly in the heat (but were radiantly heated) celled up pretty nicely anyway (with the smaller cells closer to the heat source).

If it were brought up evenly heated in a controlled kiln to an as yet unknown temp... once held at that temp for say 1/2 an hour til the temperature is even throughout the rock, then yanked out of the kiln and popped into water... VOILA!!! Even cells.

Closeup:


What remains to be seen before pursuing that (and I can't really, I don't want to crackle my blood red carnelians, that's the only off-colored one I had), is whether it will cab showing the crackles, or will fracture to pieces during grinding...

[deb193redux]

no I do not agree it is cell-like. some of the lines are parallel and cross-hatched, but mineral cells (unlike many organic cells, e.g., dino bone) are straight segments with some number of elbows. Usually the number of elbows will be fairly constant. think honeycomb. for me it relates to fracture planes in mineral, which relates to the macro-crystal habit. Other cells are fairly uniform in cross section, such as in Indonesian fossil coral.

there was regularity and symmetry of the cells in Krystee's slab.

I understand you are making an appeal to more even heating, and possibly more even quenching, to get more regular pattern of cracks, but I think you are confounding "finer" with "regular"

but I have no specific mineral or material science knowledge. just general, so this is just my thoughts and what I see in your pics.

[elementary]

Hey Helen!

Just wanted to say that I think it's awesome that you're willing to try this experiment. As to its success - I'm staying neutral. I don't see the exact results seen in Krystee's stone, but I do see the fracturing. It's just hard to see for me.

But cool work! If you do more, please show!

Lowell

[helens]

Thanks Lowell:). I'm not particularly interested in treating rocks... I barely have enough time to cab some rocks:P.

Daniel, I see what you're saying... but that doesn't mean it can't be done because 'dragon scale' agates and the other ones are already being done this way, and they ARE honeycombs, I'm just trying to reinvent the wheel here, because I don't know their exact process.

This just fascinated me, not only because of Krystee's rock (who wouldn't like more of THOSE! Or the one that Rocks2dust showed?), but because I bought a strand of INCREDIBLE vivid orangy yellow beads like that... it's really really beautiful, and I had always wondered what kind of rock it was.

I think like anything else, there's a 'trick' to it. I have no clue what that trick is, but I still think I'm on the right track (at the least, the process is mentioned multiple times online... 'quenching' that is).

Who knows... maybe it needs to be dipped in sugar first or beeswax? An opal dealer once told me the 'trick' to getting perfect andamoosa black opals was to wrap them in brown paper bag, then dunking in brown sugar before 'cooking'. What the heck? Maybe it's the glue/binder in the bag reacting with the sugar? I don't know.

There are a ton of 'tricks' in glass to get certain effects that are simple, but it might take you a million years of blowing up glass to figure out if someone didn't tell you how to do it. Another example would be silversmithing... what would make you think that you needed something like solder? Or flux? Isn't it more intuitive to assume you melt one end of silver and just stick it to another piece? Or pickle? Who would think to do that if someone didn't tell them to?

I'm satisfied that it CAN be done. I'm not satisfied that *I* can do it, but there's a trick to it I don't know yet. This matters because when I first read about it, it made NO sense... as I said, my glass violently explodes if dipped in water, I do that almost every day to get rid of waste glass on the tip of a rod or a tool. I stuck pieces of rock in my kiln, and THEY exploded or fell apart (like the white one did above). And it was easy and very fast for me to test.

That said, it's not perfect cells no, but again, I didn't heat it evenly or well. It's impossible to take pix with a SLR using your left hand, and focus. I have far less control with my left hand to hold the rock if I'm holding the camera, so this was a tough experiment to do.

Further, doing it this way, and knowing that heat can create violent reactions in rocks, made me very paranoid about my giant expensive camera lens, which due to the length of my arm holding the rock in the flame, made it impossible for the lens to be more than a foot from possible shrapnel. The heating was imperfect and uneven because of the camera. It's tough to play with a torch using only one hand, and your off hand at that.

All that said, I'm convinced it can be done, despite that I didn't quite do it. That does NOT MEAN that Krystee's rock is treated!! I said that already. Why can't that be created in a natural, but rare, process too? But I already posted Ebay beads (and I own some myself), where the cells are almost flawlessly honeycomb.

And everyone admits the 'dragon scale' agate beads are done with quenching (which are incredibly symmetrical cells), so this isn't a theory, it's trying to figure out HOW they did it without precise temperatures or directions.

Further, tonite, I began shaping that yellow piece on the grinder. Some of the cracked parts did fall out of the top, but overall, it held shape and the cracks within are intact. I'm going to vibe tumble it next and see how it polishes up, and see if the vibe tears it up.

It's actually quite interesting looking:P.

[deb193redux]

I am still skeptical that quenching can produce this effect in agate. the reason glass shatters into random shards when cooled unevenly is because it is amorphous, no crystal structure. for regular cells to occur it has to be following the crystal structure. the micro-crystalline structure of agate cannot do this.

all I know about Dragonscale agate is what I just found online. maybe I have more to learn, but so far it appears to be a surface treatment. in the faceted beads in this link, the 45-deg facet cuts have no scales, only the tops.

www.migem.com/Categories/Dragonscale/dragonscale.htm



this is like raku in pottery. it is a crackled surface.

heat shock can crack/craze/shatter rock, but it cannot produce regular cells in agate, and just because some bead merchant calls something agate does not mean it really is even agate.

[helens]

These are like the ones I have:
www.ebay.com/itm/Red-Dragon-Skin-Agate-Gem-Beads-Bracelet-/380539570628?pt=LH_DefaultDomain_0&hash=item5899ed09c4



Here's another similar set:
www.ebay.com/itm/14mm-Dragon-Skin-Agate-Gem-Beads-Elastic-Bracelet-/370700524012?pt=LH_DefaultDomain_0&hash=item564f7919ec



Can't get the pix from the 2nd one to post.

While they aren't perfectly symmetrical honeycombs, they're pretty close.

Not sure why you say it needs to follow the crystalline structure in an agate... although that does make sense logically.

Glass is amorphous, and you are absolutely right that it fractures randomly... BUT... you ever see tempered glass crackled?


I don't think it necessarily needs to be related to the crystal structure or lack of...

[helens]

Oh... I have to mention, I chose the test yellow 'carnelian' (still not sure it's carnelian, but if it's just an agate, it's still 7 MOH) because it was close to the color of my dragon skin agate beads. Now I don't have an actual hardness kit, nor have I attempted to grind the agate beads to compare, but I'm fairly certain they are not glass just from the texture and feel (since I physically own some of every type of glass made since the 1890s, and individual pieces as old as 400 BC).

Also, the outside texture of the agate beads are SMOOTH, the cracks do not extend to the outer surface of the beads... that puzzles the heck out of me, but I got a similar effect across the test 'carnelian'... the cracks are mostly INTERNAL, except in certain spots where I overheated or left the flame on too long. And, the smoothness doesn't have the feel of epoxy or 'coating'... it feels exactly like polished agate... so how is the 'dye' seeping into the 'cracks'?

Here's a terrible shot of my set and what I did with it:

[mohs]

very nice set up Helen


what about a slow quench?
hot rock buried in sand?
Perhaps that would create a slower uniform crackle effect?

I was also wondering if they used
some sort of paint on chemical
that would facilitate a fracturing?

Also it seem like your stones are small
perhaps bigger rocks
in that controlled oven process
then the quench
might snap, crackle & pop better

i really enjoyE the lay out !

[helens]

Thanks Ed:).... what layout? You mean my messy torch table:P? LOL! I should have cleaned it up before I took the shot:P. I'm messy when I make things:P.

[deb193redux]

a bigger rock would have much more heat stress and might send shards flying.

I think you need to saw one of those beads in half. I am still thinking it is a surface treatment that is cracked, and then another smooth clear surface treatment over it.

random cracks do not have to follow a crystal structure. the cracks in the tempered glass look random to me.

for fairly regular cell structure, something has to produce the regularity. I offer crystal structure. you offer nothing to produce the regularity, only tension to produce the cracks.

I am not sure the cracks in the dragon scale/skin/vein are regular, so they might be crazing/cracks in agate beads. then treated to stabilize. but this is not regular oriented cell structure like in Krystee's piece.

if you cannot theorize a basis for regularity and orientation, you need a new theory

[Deleted]

I agree, the Chinese beads are usually glass fakes. Even if you should come across some heat-quenched examples that started with real stone they would (hopefully) be put through a glass-filling or resin treatment to keep them from falling apart right away.

Amorphous and cryptocrystaline materials fracture conchoidally, i.e., lots of curved, rather than straight, path lines (as you can see in both the pictures of the beads, broken safety glass and your experimental rock). Even "straight" conchoidal cracks turn out to be subtly curved, and they will try to travel to an edge or another fracture. Some cracks will just disappear without terminating in another crack (though they are not stable), others will occur inside of other "cells." I'm seeing mostly straight sides and complete polygons in Krystee's stone, with lines forming the side of one polygon generally terminating at the points of other polygons like you would see in xtl formation (much more so than in the artificially produced examples).

Great experiment, though. I just hope that isn't your front window, lol.

[deb193redux]

I think rocks2dust just made my point, only said it better. quenching is unlikely for Krystee's slab

[Deleted]

Here is a link that shows a sliced crab fire and similar Asian fake "agates":
www.theimage.com/newgems/synthetic/synthetic12.html

[helens]

LOL! Actually, when my oldest son was small, he managed to lightly toss a marble JUST RIGHT at our tempered glass sliding glass door... and it did exactly that crazing.... then slowly fell to pieces on the ground (and I mean SLOWLY), as I watched. This was impressive, because the force of the toss was minimal, and I myself had RUN face first into that glass (I used to SPRINT through my house to get some extra exercise on my way to smoking cigs. LOL!) I run pretty darn fast, so face first was at tackle speed into the glass, and it didn't break, but a little tossed marble shattered it. That comment just reminded me of that:).

As for the surface crazing, the beads are small, so that may well be the case, but the carnelian I tested, the fractures were deep, and in the center of the stone (which is why they did not photograph so apparently).

What's my theory to explain the cracking? Don't have one. I'm not up on the science of cracking, though I recognize your logic in pointing out that glass should crack amorphously, and quartz should crack crystaline. So while I can't explain the science, I can visually see the results of my experiment this afternoon, which is a not crystalline cracking of the carnelian I used (which was not glass). And I can show it to you in a photo (posted above).

It's agate, why isn't it crystalline cracking if it must crack that way? I'm not following this logic of yours here. Are you guys saying my carnelian was glass? Then explain the jasper slabette. It didn't crack in a crystalline way either, and is even more asymmetrical than the carnelian... yet it too crackled. What happened there?

As for the science, can you explain how Krystee's naturally occurred then? That was what we were trying to figure out originally if you recall.

And just because something is duplicatable by man, doesn't mean it cannot occur in nature. Consider that we can synthesize MOH 10 diamonds and MOH 9 rubies and sapphires now, doesn't mean real diamonds, sapphire and rubies don't exist because people figured out how to make them:).

So what's your science for how Krystee's happened?

As for stabilized, already told you there is NO evidence of any stabilizing, no fracture marks on the surface. I guess they could have ground it AFTER stabilizing, but light would not refract off the stabilized cracks the same way as the material, yet you can tell by my photo that the shine is even.

[deb193redux]

you need to understand the difference between micro- and macro-crystalline. agate does not fracture in regular organized ways with planes and angles because it is micro-crystalline. Thus it fractures in curves.

My point was that to get the regularities seen in Krystee's slab, you cannot theorize agate heat fracturing. I suggested something other than agate perhaps a quartz or feldspar or a mix could fracture in regular ways due to the macro-crystal structure. But, my thought for Krystee's slab is a fossil origin.

I don't know why you cannot see the striking difference between the regular polyhedrons in Krystee's slab and the random fractures you produced. but I see it plainly.

[helens]

Ok, I get what you're saying now... you think that Krystee's is a perfectly symmetrical 'honeycomb' type of polygon structure, similar to that found in dino bone, while heat induced fractures are NOT symmetrical, and could not be made to become as symmetrical.

I see the problem here now. I see no honeycombs, where are they? I do not see a single even sided polygon structure in her rock. A polygon as defined in "all sides and angles in the structure are the same". Where's the polygon?

After carefully scouring every single cell in her photo, I found 1 pentagon - it's 2 cells northeast of the larger beige and white shape on the lower left. I used to be a 'Where's Waldo' fan, and could spot them pretty quick. I did not however count all the cells to say what % that 1 polygon represented:P.

Krystee's rock:


So maybe I'm misunderstanding again...

I see 3 'flower' type points of origin however. 1 is centered by the brown spot on the left. Other centered by the brown shadow to the lower right of that spot. Last is centered to the brown tinge to the lower left of that brown spot.

I've never seen multiple ripples like a pebble dropped in a pond that graduates in size like this in say a dinobone slice.

All 3 look like 'heat points' comparable to the center of my carnelian. So can you explain what you mean by the symmetry and crystalline structure of this?? The 'flowers' spread is sort of symmetrically graduated in size, is that what you meant?

So I thought... well, if dragon scale comes SMALL, it should also come BIG too right? Here's a pendant I found on Etsy:
www.etsy.com/listing/119258107/honey-agate-and-honeybee-copper-wrapped?ref=sr_gallery_14&ga_search_query=dragon+scale+agate+pendant&ga_view_type=gallery&ga_ship_to=US&ga_includes%5B%5D=tags&ga_search_type=all

And the photo from the above Etsy listing:


This does not look similar??

[helens]

And please look at all the photos of this Etsy listing:
www.etsy.com/listing/72681439/sea-sediment-jasper-prehnite-and-peach?ref=sr_gallery_2&ga_search_query=dragon+scale+agate+pendant&ga_view_type=gallery&ga_ship_to=US&ga_includes%5B%5D=tags&ga_search_type=all

That's got angled shine photos too... if the cracks were superficial, glass, and stabilized... why would the refraction be identical? There's no way to melt a layer of glass on top of glass WITHOUT melting the cracks right out too. Look how thin the piece is.

[helens]

Daniel, I'm not saying you are wrong. I just don't think I'm understanding exactly what you are saying.

Here's all the images together to compare:
Krystee's


Dragon Skin Agate from Etsy #1:


Dragon Skin Agate from Etsy #2: (all links are in above 2 notes):


What rock has a structure similar to the above?

A dino bone image I found in google search that I shamelessly pillaged: