rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jan 16, 2005 21:01:13 GMT -5
Over the course of the fall and winter, I've been gradually building up a bunch of agatized petrified wood to move on past coarse grind. Still not enough for a full load yet  . Anyway, most of it is earth-toned and banded like in the following pic:  But once in a blue moon I come across a very different piece. Below are two weird ones that have gone through 60/90. Any ideas what might cause this type of pattern? I'm guessing that the top one was buried while green, then cracked as it dried, allowing the cracked pattern to form when it was petrified. Sound plausible? Anyone have a better idea? The bottom one is weirder...maybe some kind of bark pattern? Does anyone have a different guess or know for a fact what causes these kinds of patterns? I like them, but I'm curious to know how they come about.  Thanks. |
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Post by cookie3rocks on Jan 16, 2005 21:12:37 GMT -5
Bark, maybe?
cookie
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Post by Toad on Jan 16, 2005 22:13:21 GMT -5
brecciated agate
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Post by Cher on Jan 16, 2005 23:33:58 GMT -5
The top one in the bottom picture looks to me like it may have weathered some (like driftwood) before it got buried and became agatized. It looks like lots of the driftwood I've picked up with the side cracks in it. Reminds me of cedar with the color and the red streaks in it. Don't quite know what to think of the bottom one except that it was probably a similar thing that happened to that piece. It doesn't look like bark to me, to many cracks in it. Could be possible that it had burned some or was exposed to extreme heat for a while before it got buried. Nice peices though, be interesting to see them polished.
Cher
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joanna
spending too much on rocks
Member since November 2004
Posts: 385
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Post by joanna on Jan 17, 2005 6:22:16 GMT -5
I was also thinking they have the texture of burned wood. Very similar to the pattern that's on the hot coals from my woodstove.
they sure look like they will turn out great. Being a wookworker I really love the look of pet. wood. I have a really nice piece (12 x 6) that has some great texture(like a weathered post) but the coloring is kind of bland.
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jan 18, 2005 3:26:54 GMT -5
I find the burnt wood theory very intriguing -- that's something that had never even crossed my mind. Guess I'll have to do some more rockhounding come springtime to see if I can't find a few more pieces that might clear things up! Thanks for responding.
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agatenut
starting to spend too much on rocks
Member since August 2004
Posts: 127
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Post by agatenut on Jan 18, 2005 7:14:11 GMT -5
That bottom piece sure looks like it has scales to me. Do some types of trees or bushes have scaled bark?
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Post by Tweetiepy on Jan 18, 2005 13:15:47 GMT -5
Stupid newbie question, but can you tumble wood? Wouldn't it become wet? and how do you know if you can tumble it?
PS: love to see the canadian quarter in pics, makes me glad I'm not alone from this frozen country (-36 deg C today) brrrr
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jan 18, 2005 18:47:10 GMT -5
You can't tumble regular wood. This is petrified wood, about 30-50 million years old. The wood has been entirely replaced with quartz (agate), so even though it sometimes looks just like fresh wood, there is no real wood there, just stone.
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Post by cookie3rocks on Jan 18, 2005 19:07:48 GMT -5
When I was a newbie (not that long ago) , people would talk about pet wood and I thought they meant their favorite stone, like "teachers pet" or (if you are old enough to remember) a pet rock.
cookie
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Post by Steve on Jan 18, 2005 19:10:07 GMT -5
If fire were the cause of the fracture pattern I would expect the color of the wood grain portions to be more black. The top one reminds me of fracture patterns I have seen in rotting wood when backpacking or camping (collecting fire wood in the Sierra mountain range - mostly evergreens). It may occur with seasonal cycles of exposure to moisture and dry. The bottom one is more of a puzzle - I would guess bark. Does the other side of that one have a different texture?
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jan 18, 2005 19:14:47 GMT -5
Just for fun, here's a piece of petrified wood (top) and a piece of regular wood, both found in about the same place in the river. These have been cleaned up... coat them with some river mud and silt and they are much harder to tell apart (except of course that the petrified wood is many times heavier than the real wood, and goes "clink" when you hit it, instead of "thud").  |
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bwalters
has rocks in the head
Member since March 2004
Posts: 557
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Post by bwalters on Jan 18, 2005 19:25:28 GMT -5
Almost ALL rocks are our 'pet' rocks, aren't they, Cookie? My favorite changes frequently! I have a bunch of pet wood from our rockhounding trip to Falls City last spring. Some of it is kinda boring, but alot of it has great patterns and colors in it. I found one good size chunk that really polished up well after cutting. It has red and green in it in a beautiful pattern. Last weekend, Llana and I went to a rock show in Fredericksburg. I found another piece of pet wood that definitely has the same burgundy red in it but haven't cut it yet so I don't know if it has any of the green in it or not. The best thing about that chunk was that it was in a 'FREE' bucket! I didn't have to pay for it or dig for it or anything!
BE
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jan 18, 2005 19:31:56 GMT -5
Steve, thanks for the comments. Here is a picture of the other side of the rock... the pattern is still there but the contrast isn't as good so it isn't quite as noticeable. On the top of the rock the colour goes to brown, and the pattern is still there. (Sorry for the photo quality, this was a rush job.) I'm not sure if burning is the cause or not, but remember that the black sootiness wouldn't likely be carried through when the wood was petrified, so I don't think colour really tells much here. The pattern was likely preserved though.  |
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Post by Tweetiepy on Jan 18, 2005 20:04:32 GMT -5
I'd sure like to find some wood like those I've seen. All I can find is clay (not a stone - I know that ) and gravel (not nice stones) I just wonder if I'd be able to find some nice specimens at some point - with my luck, I'd find something interesting and it would turn out to be non-mineral (like petrified cow patties or something). Keeping my eye open for interesting stuff.
Any way I can know what kinds of stone to tumble together and what not to put together? Or can I just plop all the pretty rocks together and hope for the best or take out what looks "done" and keep tumbling the rest?
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. Anyway, most of it is earth-toned and banded like in the following pic:
