# I found this 'rock'... What is it? (link with pics) **URL:** \ **Category:** Factual Questions\ **Created:** [March 3, 2001, 6:28am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612 "2001-03-03T06:28:45Z")\ **Posts on this page:** 18\ **Page:** 2
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [March 5, 2001, 7:07am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/21 "2001-03-05T07:07:22Z")
In this photo [http://www.classmac.com/quarter.jpg](http://www.classmac.com/quarter.jpg) What is that marking in the upper left corner? It looks like two regular dots, with a square corner to above them to the left. ---
**Author:** ![Balance](https://avatars.discourse-cdn.com/v4/letter/b/ccd318/32.png) [@Balance](https://boards.straightdope.com/u/Balance)\ **Post date:** [March 5, 2001, 7:37am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/22 "2001-03-05T07:37:30Z")
Tossing my SWAG in: Assuming that it’s a natural formation, it appears to me to be a sedimentary deposit that formed in or was shaped by slow-moving water, possibly in or near a limestone cave. The “crater” and the holes RM mentioned may indicate erosion by dripping water. The scoring on the sides doesn’t look natural to me–it’s too even; is it possible that the sample was moved there from somewhere else nearby? \ Or it could be badly-poured concrete, although the closeups look wrong for that. ---
**Author:** ![Magnum\_s\_Mustache](https://avatars.discourse-cdn.com/v4/letter/m/8797f3/32.png) [@Magnum\_s\_Mustache](https://boards.straightdope.com/u/Magnum_s_Mustache)\ **Post date:** [March 5, 2001, 7:42am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/23 "2001-03-05T07:42:54Z")
> [@](#): > > \*Originally posted by RM Mentock \* > \*\*In this photo > > [http://www.classmac.com/quarter.jpg](http://www.classmac.com/quarter.jpg) > > What is that marking in the upper left corner? It looks like two regular dots, with a square corner to above them to the left. \*\* That does look odd in that photo. But I think it’s a Mars Face sort of thing. I took it from another angle and it does not look nearly as man-made… But it is interesting. Looks almost like worm holes. Here’s the up close shot, about 60K in size: [http://www.classmac.com/holes.jpg](http://www.classmac.com/holes.jpg) Cheers, Shay ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [March 18, 2001, 6:34am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/24 "2001-03-18T06:34:07Z")
Hey Magnum I forgot to post this site last week. Check out the description of [petrified palm wood](http://www.intersurf.com/~heinrich/Palm.html). I couldn’t find any illustrations though, but that is the sort of thing I’m guessing. [Chalcedony](http://home.minerals.net/mineral/index.htm). ---
**Author:** ![escortsu](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@escortsu](https://boards.straightdope.com/u/escortsu)\ **Post date:** [March 5, 2003, 7:21pm UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/25 "2003-03-05T19:21:25Z")
Well , I am no expert , but what I see looks a lot like quartz to me, one reason is that the edges of the quartz-like white mineral where it connects to the area showing the second mineral. look like a crystal formation in the photo of the tiny globules of a second mineral formed in the indented area. And that second mineral looks like orbicular jasper to me . Anyone else feel this way? ---
**Author:** ![X\_Slayer\_ALE](https://avatars.discourse-cdn.com/v4/letter/x/bbe5ce/32.png) [@X\_Slayer\_ALE](https://boards.straightdope.com/u/X_Slayer_ALE)\ **Post date:** [March 5, 2003, 7:32pm UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/26 "2003-03-05T19:32:58Z")
Its a leeverite… ya can just leeverite thar, its just a rock. 😃 it really does look like some form of concretion. have these people look at it [http://members.tripod.com/~Larus/collectors3.html](http://members.tripod.com/~Larus/collectors3.html) ---
**Author:** ![RedDawgEsq](https://avatars.discourse-cdn.com/v4/letter/r/dbc845/32.png) [@RedDawgEsq](https://boards.straightdope.com/u/RedDawgEsq)\ **Post date:** [March 5, 2003, 8:28pm UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/27 "2003-03-05T20:28:41Z")
IANAG, but my guess is it’s a “sex stone”. V V V V V V V V V You know… V V V V V V V V V V V V Just a f\*cking rock! 😉 ---
**Author:** ![Trigonal\_Planar](https://avatars.discourse-cdn.com/v4/letter/t/0ea827/32.png) [@Trigonal\_Planar](https://boards.straightdope.com/u/Trigonal_Planar)\ **Post date:** [March 5, 2003, 8:46pm UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/28 "2003-03-05T20:46:47Z")
Just looks like well-worn cement to me 🙂 ---
**Author:** ![USCDiver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/uscdiver/32/354_2.png) [@USCDiver](https://boards.straightdope.com/u/USCDiver)\ **Post date:** [March 5, 2003, 9:13pm UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/29 "2003-03-05T21:13:51Z")
Wow, a 2 year old thread and they guy still has the pics up on his website… ---
**Author:** ![Indefatigable](https://avatars.discourse-cdn.com/v4/letter/i/9d8465/32.png) [@Indefatigable](https://boards.straightdope.com/u/Indefatigable)\ **Post date:** [March 5, 2003, 9:31pm UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/30 "2003-03-05T21:31:25Z")
Yeah, the marking that **Mentock** pointed out looks like there was something with a hinge or bolts pressed against it… and the smooth curvature and regular texture of the edges make it really look like something artificial. Remnants of a mold used to make something, or a piece that got blasted or carved out of somewhere. ---
**Author:** ![jack\_ss](https://avatars.discourse-cdn.com/v4/letter/j/c77e96/32.png) [@jack\_ss](https://boards.straightdope.com/u/jack_ss)\ **Post date:** [March 5, 2003, 10:24pm UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/31 "2003-03-05T22:24:53Z")
I’m sticking with the ‘top’ surface looking like a sedimentary lake bed. The pitting looks like drip erosion the more I look at it. No idea what caused the lines in the curved sides though. IF I found it, it would either be a paperweight or it would go out into my garden. ---
**Author:** ![sunstone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunstone/32/3372_2.png) [@sunstone](https://boards.straightdope.com/u/sunstone)\ **Post date:** [March 6, 2003, 12:00am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/32 "2003-03-06T00:00:15Z")
Based on your pictures, you might consider that you have a fossilized coral and the mineral replacement is chalcedony. But I really can’t say that with great confidence; while the pictures are good, they don’t provide the detail needed for a more certain ID. ---
**Author:** ![Terrifel](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Terrifel](https://boards.straightdope.com/u/Terrifel)\ **Post date:** [March 6, 2003, 12:46am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/33 "2003-03-06T00:46:55Z")
Petrified palmwood, almost certainly. It’s supposed to be exceedingly common in east and central Texas. In fact, it’s even the State Stone! Cool, huh? Here’s what the mineralogy folks at [UT Austin](http://www.tmm.utexas.edu/npl/mineralogy/Texas_Minerals/) have to say about it, and here’s what [some guy](http://manly.delconet.com/klahn/mville.html) has to say on the same topic. ---
**Author:** ![Terrifel](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Terrifel](https://boards.straightdope.com/u/Terrifel)\ **Post date:** [March 6, 2003, 12:49am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/34 "2003-03-06T00:49:40Z")
Ahem, [a more direct link](http://www.tmm.utexas.edu/exhibits/treasures/ppalm_wood.html) to the petrified palmwood info at UT Austin. ---
**Author:** ![Cillasi](https://avatars.discourse-cdn.com/v4/letter/c/71e660/32.png) [@Cillasi](https://boards.straightdope.com/u/Cillasi)\ **Post date:** [March 6, 2003, 1:28am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/35 "2003-03-06T01:28:41Z")
It looks like a piece of cement/concrete that was originally put down against a screen-like surface and accumulated a buildup of calcite. ---
**Author:** ![El\_Zagna](https://avatars.discourse-cdn.com/v4/letter/e/d2c977/32.png) [@El\_Zagna](https://boards.straightdope.com/u/El_Zagna)\ **Post date:** [March 6, 2003, 1:32am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/36 "2003-03-06T01:32:10Z")
I grew up in central Texas - Marlin, Texas to be exact. There was a particular hill where my family would go on picnics, and along the slope of the hill we would find rocks similar to the one you have. A paleontologist was doing a dig in the area once, and we had him identify some of our better finds. Several of our fossils he identified as a [chambered nautilus](http://www.math.nmsu.edu/breakingaway/Lessons/chnautilus1/chnautilus.html). That could be what you have. Your piece has the sort of spiral, ribbed shape that would be consistent with what I have seen. The crystalline grid patterns may be the result of the fossilization process. I’ll be very interested if someone can definitively identify this. ---
**Author:** ![Gyrate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gyrate/32/3588_2.png) [@Gyrate](https://boards.straightdope.com/u/Gyrate)\ **Post date:** [March 6, 2003, 1:35am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/37 "2003-03-06T01:35:11Z")
[Charlie Brown] I got a rock. [/Charlie Brown] 😃 ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [March 6, 2003, 5:46am UTC](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612/38 "2003-03-06T05:46:41Z")
> [@](#): > > \*Originally posted by Terrifel \* > **Petrified palmwood, almost certainly. It’s supposed to be exceedingly common in east and central Texas. In fact, it’s even the State Stone! Cool, huh?** Very cool, **Terrifel**. It looks like petrified palm wood is also the [Louisiana State Fossil](http://www.intersurf.com/~chalcedony/Palm.html). My last post to this thread was two years ago, and I thought it died and the OP lost interest. But it’s back, thanks to **escortsu**. My links are no longer good, but you might want to compare the outside ring of this [Petrified Palm Wood Slab](http://www.curiogrove.com/petwood-palm/palm-bpw001.htm) to [this view](http://www.classmac.com/reverse.jpg) of the original. The original was found in central Texas, and it sure sounds like PPW is everywhere around there. This just may not be the best preserved specimen. [Previous page](https://boards.straightdope.com/t/i-found-this-rock-what-is-it-link-with-pics/56612.md?page=1)