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Post by velodromed on Mar 24, 2023 17:55:20 GMT -5
![](https://res.cloudinary.com/dtgm9gehz/image/upload/v1679673851/bktbfx04tu9dgbvhluub.jpg) I’m still figuring out how to properly attach photos instead of just the links, so bear with me please. The kid and I found this while hunting for rocks recently. Initially I thought it was some kind of building material that had gotten mixed in. But when I got online and searched, it seems very similar to gypsum. It is soft, (but not flexible), and will easily flake off in skinny 1-2 inch strands. It’s very light as well. does anybody have any ideas what it could be?
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Post by velodromed on Mar 24, 2023 17:56:30 GMT -5
OK, cool. The pictures work and my thumb looks like hell… but that’s what happens when you have bad aim with a hammer.
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Post by vegasjames on Mar 24, 2023 20:06:22 GMT -5
Looks more like petrified wood. Does not fracture like gypsum. Gypsum would also be very soft.
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Post by velodromed on Mar 24, 2023 22:11:05 GMT -5
Looks more like petrified wood. Does not fracture like gypsum. Gypsum would also be very soft. It’s very soft actually. I can dig my nails into it quite easily and pull chucks out. I have buckets of petrified wood and it’s completely different from that. It’s so light it may float even.
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Post by vegasjames on Mar 25, 2023 1:47:53 GMT -5
Looks more like petrified wood. Does not fracture like gypsum. Gypsum would also be very soft. It’s very soft actually. I can dig my nails into it quite easily and pull chucks out. I have buckets of petrified wood and it’s completely different from that. It’s so light it may float even. Might have to run a few simple tests such as finely powdering some and see if it reacts to acid. And heating a small pieces and see if it fuses or becomes powdery.
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Gypsum?
Mar 25, 2023 11:22:41 GMT -5
via mobile
Post by realrockhound on Mar 25, 2023 11:22:41 GMT -5
Agreed. Petrified wood
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Gypsum?
Mar 25, 2023 12:13:34 GMT -5
Post by velodromed on Mar 25, 2023 12:13:34 GMT -5
It’s very soft actually. I can dig my nails into it quite easily and pull chucks out. I have buckets of petrified wood and it’s completely different from that. It’s so light it may float even. Might have to run a few simple tests such as finely powdering some and see if it reacts to acid. And heating a small pieces and see if it fuses or becomes powdery. I soaked it in 20% strength vinegar and also CLR without affect to the material. I hadn’t thought of heating it. What would be the best way? Give me a idea and I will follow… much appreciated!
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Gypsum?
Mar 25, 2023 12:21:14 GMT -5
Post by velodromed on Mar 25, 2023 12:21:14 GMT -5
I have a lot of agate/Jasper/chert petrified wood, have several pieces that are lime stone, some that are basically slate…but I’ve never seen something made of this material. It’s so light and falls apart easy, but it’s not powdery. Almost reminds me of Tourmaline, except it’s not quite as hard. I think. But I’ve only held with Tourmaline a couple times. If it is petrified wood, I’m very curious what it’s made of. I have soaked it in 20% vinegar, also CLR without affect so it’s not calcium/lime based.
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Post by rmf on Mar 25, 2023 18:41:48 GMT -5
Yes I agree with others it is badly weathered P. Wood.
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Gypsum?
Mar 25, 2023 19:15:26 GMT -5
via mobile
Post by Peruano on Mar 25, 2023 19:15:26 GMT -5
In my environs it would poorly or nonsilicated wood (in fact often partially opalized wood or wood on the way to being the pet wood that we all look for and expect). Explore the inside and you may find black opalized crevices; you can polish it and see cell structure, growth rings and branch bases. There are known sites in Nevada, New mexico, and I believe California. It can be polished but is both soft and brittle. I often think of old driftwood when I first find it on the ground.
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Post by vegasjames on Mar 25, 2023 22:14:14 GMT -5
Might have to run a few simple tests such as finely powdering some and see if it reacts to acid. And heating a small pieces and see if it fuses or becomes powdery. I soaked it in 20% strength vinegar and also CLR without affect to the material. I hadn’t thought of heating it. What would be the best way? Give me a idea and I will follow… much appreciated! Propane torch will work to drive out any water if it is a hydrated mineral.
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Post by velodromed on Mar 26, 2023 0:24:10 GMT -5
I soaked it in 20% strength vinegar and also CLR without affect to the material. I hadn’t thought of heating it. What would be the best way? Give me a idea and I will follow… much appreciated! Propane torch will work to drive out any water if it is a hydrated mineral. Cool, I have one of those. What exactly am I looking to happen that will indicate what it is or isn’t? Sorry for all the questions but this is a completely new understanding I’m working on here. I appreciate your help very much.
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Post by vegasjames on Mar 26, 2023 3:19:46 GMT -5
Propane torch will work to drive out any water if it is a hydrated mineral. Cool, I have one of those. What exactly am I looking to happen that will indicate what it is or isn’t? Sorry for all the questions but this is a completely new understanding I’m working on here. I appreciate your help very much. If it were gypsum, which is hydrated calcium sulfate, then the torch would cause the gypsum to lose water forming an anhydrite powder. If you have a borosilicate test tube then you could heat the sample gently in the test tube and if it is gypsum then you should see a build up of water vapor in the test tube as the water is drive out of the gypsum.
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Post by Peruano on Mar 26, 2023 6:24:46 GMT -5
If I'm correct in your material being similar to my NM material, this is what it will polish like if you have the black opal inclusions. Sorry, I don't have any of the rough in my photo stash. ![](https://rockshow.rocktumblinghobby.com/i.php?/upload/2021/11/15/20211115110117-d032173a-me.jpg) Like a lot of other porous rocks, this material will stick to your tongue or a wet finger due to its pulling the water away from a wet surface. Probably works best on a slab or flat recently cut surface.
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Post by velodromed on Mar 26, 2023 10:48:20 GMT -5
Cool, I have one of those. What exactly am I looking to happen that will indicate what it is or isn’t? Sorry for all the questions but this is a completely new understanding I’m working on here. I appreciate your help very much. If it were gypsum, which is hydrated calcium sulfate, then the torch would cause the gypsum to lose water forming an anhydrite powder. If you have a borosilicate test tube then you could heat the sample gently in the test tube and if it is gypsum then you should see a build up of water vapor in the test tube as the water is drive out of the gypsum. Thank you, I do have something that will work for that and will try it. Much appreciated!
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Post by Peruano on Mar 26, 2023 10:57:12 GMT -5
There is a good discussion for opalized wood in geology.com ....search opalized wood. Soft, low specific gravity etc.
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Post by Peruano on Mar 26, 2023 11:25:43 GMT -5
Here's an unprocessed piece which shows a thin layer of the black opal that is characteristic of my sites in NM. It can be thick or thin, located in cracks or solid masses but still in form of the wood it is replacing. As I understand it, opal is a silica product on its way to being chalcedony so, its possible that all the pretty pet wood you have seen went through this stage in its ultimate formation. ![](https://rockshow.rocktumblinghobby.com/i.php?/upload/2023/03/26/20230326091937-3c7a5a30-me.jpg)
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Post by vegasjames on Mar 26, 2023 19:43:18 GMT -5
Here's an unprocessed piece which shows a thin layer of the black opal that is characteristic of my sites in NM. It can be thick or thin, located in cracks or solid masses but still in form of the wood it is replacing. As I understand it, opal is a silica product on its way to being chalcedony so, its possible that all the pretty pet wood you have seen went through this stage in its ultimate formation. ![](https://rockshow.rocktumblinghobby.com/i.php?/upload/2023/03/26/20230326091937-3c7a5a30-me.jpg) All chalcedonies are the dehydration product of opal. So opalized wood is younger than "agaatized" wood. As the water content of the opal drops below 3% the opal starts to crystallize and gains density as it converts in to some form of chalcedony.
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Post by velodromed on Mar 27, 2023 7:50:25 GMT -5
Here's an unprocessed piece which shows a thin layer of the black opal that is characteristic of my sites in NM. It can be thick or thin, located in cracks or solid masses but still in form of the wood it is replacing. As I understand it, opal is a silica product on its way to being chalcedony so, its possible that all the pretty pet wood you have seen went through this stage in its ultimate formation. ![](https://rockshow.rocktumblinghobby.com/i.php?/upload/2023/03/26/20230326091937-3c7a5a30-me.jpg) That is very interesting! I have been trying to research and understand what opal is lately. I have quite a few petrified woods that are covered with black material. Some of them seem to be that way all the way through while others have the beautiful wood grain and colors underneath the black. I’ve been wondering what the black covering is, I was assuming it was some kind of slate type product or something. I will do a search on opal here on the site today and try to figure out more about it. Many thanks man!
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Post by velodromed on Mar 27, 2023 7:51:52 GMT -5
Here's an unprocessed piece which shows a thin layer of the black opal that is characteristic of my sites in NM. It can be thick or thin, located in cracks or solid masses but still in form of the wood it is replacing. As I understand it, opal is a silica product on its way to being chalcedony so, its possible that all the pretty pet wood you have seen went through this stage in its ultimate formation. ![](https://rockshow.rocktumblinghobby.com/i.php?/upload/2023/03/26/20230326091937-3c7a5a30-me.jpg) All chalcedonies are the dehydration product of opal. So opalized wood is younger than "agaatized" wood. As the water content of the opal drops below 3% the opal starts to crystallize and gains density as it converts in to some form of chalcedony. I did not know this! I will get on geology.com and research. Really cool of you to point this out.
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