Anyone know what this is?

[DanaM]

My boss gave me two buckets of rocks and slabs that his father-in-law had slabbed, I was thinkin it was petrified wood judging by the rough side
of some of the pieces. But I really don't have a clue I stitched one side of a slab(see picture) and it kind of flake but is tough and looks like a quartzite.
I will bring some to the Classic. Wonder if cooking it will help? They gave his rock saw away it was big oil bath one to

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[DustinDees]

we have a lot of petrified wood around the yakima valley and the outside edge and grain of the colors looks right for petrified wood, but around here the wood is almost always replaced with brown agate, little blue and white. i assume that whatever high silica material replaces the wood is what determines the color and knapability of the "wood". I may very well be completely wrong  . hope this helps.

Dustin D

[Hillbilly]

I'd say you're probably right with the peterfried wood. Some heat would probably help it. Purty stuff wahtever it is- save me a slab.

[DanaM]

Will do Steve, I tried pushing some flakes off but they don't go far Any Idea what temp it should be cooked at and for how long?
I have an old muffle furnace from work that goes up to about 1000 degrees Celius

[sailordad]

i would have to say,with limited knowledge,that it looks alot like petrified wood also.

hey ifn you want to send me a piece i would be very appreciative

good luck and have fun with that wood/rock Dana

                                                                             peace,
                                                                                   tim

[cowboy]

I agree Dana, looks like wood - sure is purty. I'd bury it in the ground and cook it for a day, not sure what temp that is though. Around 600 I think.

[sailordad]

did i forger to mention,  you are one lucky s.o.b..

[DanaM]

Thanks guys, I know for sure its not knappable as is, welll maybe James can knap it but I can't.

Tim remind me after the classic and I will send ya some

[mullet]

 I've knapped petrified wood and is chips really nice after you cook it around 600dgs like Paul said. It looks like some I brought back from Colo., kinda chipped like Agate after it was heat treated.

[hawkbow]

looks kind of like picture Agate.. ask Wolf watcher.. he will know what it is . and what temperature to heat treat it.. old rock hound that he is Hawk

[DanaM]

I will try cooking some at 600 but for how long

I liberated a furnace from work it goess up to 2200 degrees F, maybe I can rurn it into obsidain

[cowboy]

Dana: I've never tried a kiln or furnace but have read to ramp it up slowly, like 50 degrees every four hours until you reach 600. Then let it soak at that temp for 12 hours or so, then ramp it back down accordingly till you hit around 100 degrees and your done. Those sawn slabs, i'm sure can go quicker - but I don't want ya to ruin your rocks either.

[leapingbare]

Danna be easy cooking it.. i say no hotter the *500.
you need to get a metal box and feel it with sand and evenly place those slabs in the sand so there not touching. Then put that in your kiln set it to *300 let it set for a few hrs. and then ramp it up *50 every 45mins or so till you reach *500 then let it stay at *500 for 4-6hrs. then just cut it off let it cool for at least 12hr before doing anything with it.

[DanaM]

Hmm getting a metal box to fit in the furnace is gonna be tough as the cavity is quite small. Guess I will just try a few pieces and see what happens eh

[Wolf Watcher]

Dana:  There seems to be more than one type of material in your bucket.  The swirly stuff is some kind of agatized material, but if the piece you tried to flake is one of those pieces it may not be knappable.  At least it will take some serious heat treating.  Do you know if it has been out in the weather as moisture in the stone can cause trouble when heat treating???  Believe it or not the rule is that slabs require more heat than nodules.  Has something to do with mass and a large core distributes heat better than a thin slab!  I have a couple of DC Waldorf's "Roasting Rocks" and will bring you a copy to the Classic.  I have several types of agatized material and some of it like the sponge is not knappable material.  If you try to treat it make sure you have it covered with a good amount of dry sand.  Its better to try the first time at a low temperature to see if there is any change and then crank it up some until you get some acceptable results.  Ramp up and down.  Joe