braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Aug 14, 2019 16:28:31 GMT -5
In another thread it was said that heating up/cooking rocks might enhance it's color. One of the suggested ways was to do this was in a crockpot with kitty litter buffering the rocks from rapid temperature changes. Some were wondering if a crockpot was hot enough to do the job. I had everything on hand and decided to give it a go and see what happens. It turned out to be more of an adventure in what not to do than getting any positive results. The plan was one day with crockpot on low heat, one day on high heat and one day to cool off. For day one I put tea towels on the lid to help hold the heat in...you can see in photo one that wasn't a good idea as the towel started to scorch after a few hours. I ditched the towel idea especially since a day on high heat was next so (brainwave) I tried oven mitts instead (photo 2)...much better at holding heat in with less fear of burning down the house. But after a day on high heat it was obvious they worked too good cause when I took them off the lid knob was melted! (photo 3). OK... all info stored for future reference but I got a cooldown day left before I get to see if anything wonderful happened colorwise but sadly no noticeable change was evident (photo 4 and 5 are wet photos before and after). I tried to arrange rocks in photo 5 the same as photo 4 but a couple of them that look like there was a change are just the wrong side showing if you understand what I'm saying. So bottom line crockpot cooking didn't enhance anything except maybe my insurance rates but silver lining I get to tell a story 1 2 3 4 5
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Post by parfive on Aug 14, 2019 17:05:46 GMT -5
I don’t need another reason not to live in multi-family housing but . . . : )
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Post by parfive on Aug 14, 2019 17:07:08 GMT -5
I’ve done tiger eye on top of the woodstove. That worked.
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Post by rockpickerforever on Aug 14, 2019 23:45:26 GMT -5
In another thread it was said that heating up/cooking rocks might enhance it's color. OK... all info stored for future reference but I got a cooldown day left before I get to see if anything wonderful happened colorwise but sadly no noticeable change was evident (photo 4 and 5 are wet photos before and after). I tried to arrange rocks in photo 5 the same as photo 4 but a couple of them that look like there was a change are just the wrong side showing if you understand what I'm saying. So bottom line crockpot cooking doesn't enhance anything except maybe my insurance rates but silver lining I get to tell a story You can bet it enhances your electric bill, lol. You don't know unless you try it. You learned a few things, and you had fun. So glad you didn't burn your house down. Thank you for sharing your story. Have to add - your toasted tea towel looks like the Shroud of Turin... But from off a rabbit or something, not a person.
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Post by rmf on Aug 15, 2019 3:44:49 GMT -5
I have taken TN Horse Mtn Agate (Chalcedony which varies from white to red) which were brown and put them in a Stainless Steel pan covered with sand and placed them in the oven. I turned up the temp and slowly brought them up to 200 deg for 4 hrs then turned up the heat real slow every 2hrs until they were at 250F in another 4 hrs. Once at 250F for a good long time I upped the temp to 350F for 2hr then 400F then max. Turned the oven off when I went to bed and let it cool over night. In the morning I was rewarded with nice carnelian. Thes stomes had been rough tumbled prior to the heat treatment then finished tumbled after. Sorry they were long gone before I ever heard about this forum.
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Post by orrum on Aug 15, 2019 6:57:31 GMT -5
Agates take way more heat than a crockpot, skillet or turkey roaster can give you. Wonderstone, Flintridge flint, show a color response.
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braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Aug 15, 2019 9:25:29 GMT -5
Have to add - your toasted tea towel looks like the Shroud of Turin... But from off a rabbit or something, not a person. Ha...I thought the same only I saw an evil pig with it's eyes closed...
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,676
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Post by Fossilman on Aug 15, 2019 9:34:13 GMT -5
There is a recipe for Flintridge on this forum, I'm sure I have one too, but never thought of cooking agate... I do all mine outside (My wife would kill me if I did that in the house) hahaha.. Also remove the ceramic liner and you get more temp out of the equipment... I use contruction sand that has been already dried out... Are ya' going for it again? Hope so.... Good luck!
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braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Aug 15, 2019 9:34:53 GMT -5
I have taken TN Horse Mtn Agate (Chalcedony which varies from white to red) which were brown and put them in a Stainless Steel pan covered with sand and placed them in the oven. I turned up the temp and slowly brought them up to 200 deg for 4 hrs then turned up the heat real slow every 2hrs until they were at 250F in another 4 hrs. Once at 250F for a good long time I upped the temp to 350F for 2hr then 400F then max. Turned the oven off when I went to bed and let it cool over night. In the morning I was rewarded with nice carnelian. Thes stomes had been rough tumbled prior to the heat treatment then finished tumbled after. Sorry they were long gone before I ever heard about this forum. I was thinking afterwards it would probably have been easier to see any changes using polished rocks vs the rough stuff I used...
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,676
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Post by Fossilman on Aug 15, 2019 9:35:51 GMT -5
Agates take way more heat than a crockpot, skillet or turkey roaster can give you. Wonderstone, Flintridge flint, show a color response. Orrum,(the "Master" of cooking and knapping) listen to him.... Thumbs up
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braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Aug 15, 2019 9:40:20 GMT -5
Are ya' going for it again? Hope so.... Good luck! Undecided...but for sure not in a crockpot
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Post by rockpickerforever on Aug 15, 2019 10:12:39 GMT -5
Have to add - your toasted tea towel looks like the Shroud of Turin... But from off a rabbit or something, not a person. Ha...I thought the same only I saw an evil pig with it's eyes closed... That also occurred to me...
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braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Aug 15, 2019 12:47:58 GMT -5
Agates take way more heat than a crockpot, skillet or turkey roaster can give you. Wonderstone, Flintridge flint, show a color response. Hmmm... this got me thinking...I got some "borderline bland" solid color local jasper I'm thinking might be worth a try... do you think a crockpot run of polished jaspers would diminish the shine? Even if it does I'd maybe have more info for future rockhounding...
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Post by bobby1 on Aug 15, 2019 18:11:37 GMT -5
I just submitted my monthly "Bench Tips" article for Rock and Gem Magazine. It was on heat treating agate. I use a burnout kiln for casting flask burnout activities. It is an older unit that doesn't have an electronic controller for the heat adjustment. Generally, most solid color rocks don't do much in the color-change category. I focused on heat treating agate slabs. It requires that the agate to have been exposed to a lot of iron during its formation. If the rock exhibits orange to red colors it probably has enough iron in it to change to redder or sometimes a brown color. I had one small slab that had orange color on the surface but a milky color inside. I had great hopes for the whole thing to turn red with heating but, alas, nothing beyond the skin color darkening a bit. Obviously, no iron had migrated beyond skin deep. The rest of the slabs did have significant darkening. I put an aluminum tray in the chamber and added sand to the bottom and stacked the slabs with 1/2" of sand between the slab layers and equally on top of the slabs. I turned the rheostat dial to the lowest position and let the chamber heat up slowly. It reached 275 within about 6 hours so I turned the dial up one increment and went to bed. The next morning it was at 375 so I left it for 3 hours and turned the dial up one more increment. After about 3 hours it rose to 475. I left it there for 3 hours then I turned the oven off and went to bed. The next morning it was fully cooled down so I removed the slabs. With the one exception, all of the slabs had darker red colors. Two important things: 1. don't hurry the heat up or cool down cycles or you will fracture the materials. 2. Never open the oven door during the cycles for the same reason. Bob
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Post by rmf on Aug 15, 2019 18:51:53 GMT -5
braat I was not sure if the polished surface would be more "sealed" and prevent water from escaping and crack the rock. Tumble finished would be a good experiment.
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agatemaggot
Cave Dweller
Member since August 2006
Posts: 2,195
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Post by agatemaggot on Aug 15, 2019 20:55:23 GMT -5
Got a list of temperatures from a geologist in Oregon for the temps. for most stone. Most stone took 500 degrees and up except for Montana Agate which was 450 degrees. I ran a few slabs of stone in an old roaster oven that could push 600 degrees. I started at 200 and let it soak for 2 hours to bleed off moisture and then bumped it up 50 gedrees per hour until I got to Holy Crap that's hot and after 4 hours turned it off and went to bed. I left everything sealed up over the weekend and opened it up Monday afternoon. I saw color change and the rock worked a lot easier in grinding and in pressure flaking also ! New roasters can not get diddle for temperatures but you may be able to find an older cooker on E-Bay for little of nothing, most have little or no use as most Women don't mess with them and use their ovens ! I picked mine up for $12.00 . I use Garnet sand I got from a water jet operator that had been used once. They can only use the sand in cutting one time because it is contaminated with the previous material that was cut. Not sure but it might be of use in tumbling operations and it's free, bring your own buckets !
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braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Aug 15, 2019 21:29:19 GMT -5
Wow...lots of good info coming out on this rock cooking stuff. I'm going to have another go at the crockpot with the tumble polished solid color jaspers I talked about up thread. I'm curious and others seem interested as well so when I get to it I'll post results like I did here (hopefully with less drama)...
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Post by orrum on Aug 16, 2019 6:17:40 GMT -5
Let the rock soak at the high heat overnite. Mookaite and wonderstone have a great response. There are flint knapping temp charts but they are for ease of knapping. Color change happens at lower temps. With a turkey roaster take the pan out and you get 60-75 degrees more. Use insulation under the lid like you use in the house, just fold it into a thick pad. Put a big rock on the Lind to keep it mashed down on the insulation.
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braat
spending too much on rocks
Member since December 2016
Posts: 350
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Post by braat on Aug 16, 2019 10:42:26 GMT -5
Let the rock soak at the high heat overnite. Mookaite and wonderstone have a great response. There are flint knapping temp charts but they are for ease of knapping. Color change happens at lower temps. With a turkey roaster take the pan out and you get 60-75 degrees more. Use insulation under the lid like you use in the house, just fold it into a thick pad. Put a big rock on the Lind to keep it mashed down on the insulation. More good info. Tks! Don't know why I didn't think of insulation UNDER the lid...too logical I guess and I'll cook up some tumble polished mookaite that doesn't look as good ( color wise) as the rest and see what happens as well. I'm curious to see if the shine survives as well as any color changes that might happen...
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Post by Pat on Aug 16, 2019 12:42:36 GMT -5
Several years ago, I cooked one rock embeddef sand in a crockpot. After several days, the mustard rock was red. Much better. I posted pictures on here, but haven’t found them yet. I’ll try to dig it up. I think I got the idea from jamesp.
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