TomTBD Posted November 3, 2017 Share Posted November 3, 2017 Hi I am new to this forum. I live in Ca and collect minerals, fossils and as an amateur photographer, I am photographing some of my collections. These photos are of an unopened small geode (3 cm, or 1.25 inches tall). They are all of 1 specimen taken at different angles. Many decades ago I received a bag of small geodes all formed in the same light green volcanic ash. This was among them. No other geodes in the bag had this texture or pattern on the outside. I put it aside thinking it may be a fossilized impression from a prehistoric reptile or tortoise foot. I have never gotten a definitive answer. Sadly I can’t recall for certain the location for the source of the geodes, but perhaps it was Chihuahua Mexico. Is this a fossil, or merely some crystallization causing the surface to appear this way? Any help would be appreciated Thanks Tom Link to comment Share on other sites More sharing options...
ynot Posted November 3, 2017 Share Posted November 3, 2017 Welcome to TFF! I have never seen a geode that looks like that. I think it is a mineral deposit, but not sure what minerals are in it. Neat piece. Tony Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
TqB Posted November 3, 2017 Share Posted November 3, 2017 Great specimen! - I think it's a concretion with a counter-septarian structure as in fig. D, this paper. Seilacher concretion morphologies (Sorry, thought that was the actual link but the pdf is on the forum somewhere - just click the "fossil forum" search result if you want it.) (We've seen similar things on here before. e.g http://www.thefossilforum.com/index.php?/topic/64412-looking-back-at-one-of-my-older-fossils-distorted-root-or-siderite-nodule/ ) Tarquin Link to comment Share on other sites More sharing options...
abyssunder Posted November 3, 2017 Share Posted November 3, 2017 That's it, Tarquin! " In a less spectacular version of such counter septarian structures, the tangential cracks did not propagate spirally. Instead they formed a round knob in the center of each first-order polygon, thus mimicking the nuclei in a cellular tissue (Fig. 15 (d)). This suggests that the defoliating cracks started from the polygonal cracks of the previous order and propagated towards the center of the enclosed area. " - A. Seilacher " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
GeschWhat Posted November 3, 2017 Share Posted November 3, 2017 What they said! Beautiful! Lori www.areallycrappystory.com/fossils www.facebook.com/fossilpoo Link to comment Share on other sites More sharing options...
TomTBD Posted November 3, 2017 Author Share Posted November 3, 2017 Thanks for the quick replies Not what I had hoped for, but what I had assumed for all these years. The pattern just looks so "organic". Like this picture of crocidile skin: Anyway, thanks again for looking into it Tom Link to comment Share on other sites More sharing options...
ynot Posted November 3, 2017 Share Posted November 3, 2017 The problem I have with this being a counter septarian is two fold. 1. The structure is 3 dimensional. 2. There is a distinct color difference between the central disk/ball (black) and the surrounding polygonal structures. 3. I see what look like botryoidal structures on some of the center structures. Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
JohnBrewer Posted November 3, 2017 Share Posted November 3, 2017 That’s a cool rock. Almost looks human made. John Map of UK fossil sites Link to comment Share on other sites More sharing options...
Fossildude19 Posted November 3, 2017 Share Posted November 3, 2017 On 11/3/2017 at 3:36 PM, ynot said: The problem I have with this being a counter septarian is two fold. 1. The structure is 3 dimensional. 2. There is a distinct color difference between the central disk/ball (black) and the surrounding polygonal structures. 3. I see what look like botryoidal structures on some of the center structures. Wouldn't that be 3-fold? Actually, the counterseptarian in the older post from Icycatelf is 3 dimensional, as well. The color is odd, but that could be an accumulation/glutination of a certain mineral. Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
ynot Posted November 3, 2017 Share Posted November 3, 2017 12 minutes ago, Fossildude19 said: Wouldn't that be 3-fold? Thought of the 3rd while typing and forgot to correct the lead sentence. Oh well. Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
abyssunder Posted November 3, 2017 Share Posted November 3, 2017 19 minutes ago, Fossildude19 said: Actually, the counterseptarian in the older post from Icycatelf is 3 dimensional, as well. The color is odd, but that could be an accumulation/glutination of a certain mineral. other examples: " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
ynot Posted November 3, 2017 Share Posted November 3, 2017 1 hour ago, abyssunder said: other examples: They do not look the same to Me. These examples all show an even grain of (mostly) one color. The original object does not correspond to that criteria. Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
TomTBD Posted November 3, 2017 Author Share Posted November 3, 2017 I should mention that this stone has been handled a lot. I have had it for about 30 years. Perhaps that has caused some of the raised areas to darken, but the detail has always been pronounced so I’m not sure. It has been a while. Tom Link to comment Share on other sites More sharing options...
KimTexan Posted January 17, 2018 Share Posted January 17, 2018 Wow, this post never got figured out? I was searching a term and this came up and I started reading it. I was so curious to find out what it was. Bummer that it’s still a mystery. I know I’ve seen this or something like it before. Link to comment Share on other sites More sharing options...
Carl Posted January 17, 2018 Share Posted January 17, 2018 I absolutely agree that it is another counter septarium. And I FINALLY found the shot of one I took in the field several years ago. Link to comment Share on other sites More sharing options...
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