(Julia) Posted November 3, 2016 Share Posted November 3, 2016 Sorry about the title and tags. I don't know what to say. Tags are hard too. Anyway, give me a name please so I can go learn. Link to comment Share on other sites More sharing options...
caldigger Posted November 3, 2016 Share Posted November 3, 2016 Please state where found, age of deposit if known, etc.,etc. pertinent information makes the ID process much easier. Link to comment Share on other sites More sharing options...
Fossildude19 Posted November 3, 2016 Share Posted November 3, 2016 Looks to me like a concretion, or septarian nodule. 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...
(Julia) Posted November 3, 2016 Author Share Posted November 3, 2016 If only. I found it in a creek bed in Round Rock TX, just north of Austin. Link to comment Share on other sites More sharing options...
Fossildude19 Posted November 3, 2016 Share Posted November 3, 2016 Bedrock Geology of the Round Rock Area. 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...
Vieira Posted November 4, 2016 Share Posted November 4, 2016 I agree with a concretion. Link to comment Share on other sites More sharing options...
digit Posted November 4, 2016 Share Posted November 4, 2016 +1 for septarian nodule--at least that's the feeling I got when looking at it. Cheers. -Ken Link to comment Share on other sites More sharing options...
fossiling Posted November 5, 2016 Share Posted November 5, 2016 +10000000 for septarian nodule. Keep looking! They're everywhere! Link to comment Share on other sites More sharing options...
Ludwigia Posted November 5, 2016 Share Posted November 5, 2016 I hate to say this, but.... Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
tmaier Posted November 5, 2016 Share Posted November 5, 2016 "I hate to say this, but.... " What is it, Batman? Link to comment Share on other sites More sharing options...
Ludwigia Posted November 5, 2016 Share Posted November 5, 2016 You have 3 guesses Robin Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
ynot Posted November 6, 2016 Share Posted November 6, 2016 Looks like a limestone with some crystallized fossils that have eroded. Tony PS does not look like a concretion or septarian to Me. 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...
(Julia) Posted November 6, 2016 Author Share Posted November 6, 2016 To me, it looks like shell... the top layer and the wavy surface. Like a clam. But where the "shell" wore away, there's the honeycomb pattern. How can I tell? Link to comment Share on other sites More sharing options...
(Julia) Posted November 6, 2016 Author Share Posted November 6, 2016 inoceramid... Shell Ultrastructure (Schematic)... prismatic layer? No? Link to comment Share on other sites More sharing options...
doushantuo Posted November 6, 2016 Share Posted November 6, 2016 the hexagonal pattern in the septarian nodule are shrinkage cracks,Julia. The calcite prisms shown in Abyssunder's post (taken from a useful Harries/ Kauffman article )are an ultrastructural feature,in principle not visible with the naked eye Link to comment Share on other sites More sharing options...
ynot Posted November 6, 2016 Share Posted November 6, 2016 Can You post pictures that show the whole thing from top, bottom and sides? The only picture in the original post that shows the whole rock is from an oblique angle, This leaves only speculation on the overall shape. 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...
(Julia) Posted November 6, 2016 Author Share Posted November 6, 2016 Yes, of course. Link to comment Share on other sites More sharing options...
(Julia) Posted November 6, 2016 Author Share Posted November 6, 2016 Link to comment Share on other sites More sharing options...
ynot Posted November 6, 2016 Share Posted November 6, 2016 I think that the "shell" layer is a mineral vein. The ripple structure is called "slickensides" and is what happens when the 2 sides of the crack were pushed against each other before they separated and then the mineral filled the crack, preserving the shapes. 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...
doushantuo Posted November 6, 2016 Share Posted November 6, 2016 Tony might be right on the dot. Often a silica gel forms during cataclasis(Kirkpatrick/Rowe/White/Brodski,GEOLOGY,2013). The gel can act as a weakening mechanism,promoting further cataclasis. Flow banding and comminution of sedimentary particles are some of the petrographic features that should be visible Link to comment Share on other sites More sharing options...
tmaier Posted November 6, 2016 Share Posted November 6, 2016 I'm with schlickensides. Link to comment Share on other sites More sharing options...
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