jeromebe Posted June 22, 2016 Share Posted June 22, 2016 I saw this comming out of cliff where I find many calamite fossils. I was wondering if it might be something. I am talking about the black tarrish rock thing comming out of cliff. Link to comment Share on other sites More sharing options...
CraigHyatt Posted June 22, 2016 Share Posted June 22, 2016 (edited) I don't see a fossil. Maybe ironstone. Let's see what experts say. Edit: I'm jealous of that purpurite, if that's what it is. I want a nice chunk for my desk. ;-) Edited June 22, 2016 by CraigHyatt Info: Craig Hyatt, retired software/electrical engineer Experience: Beginner, fossil hunting less than a year Location: Eagle Pass, TX USA on the border with Mexico, hot dry desert Formation: Escondido, Marine, Upper Cretaceous Materials: Sandstone, Mudstone, Shale, Chert, Chalk Typical: Thalassinoides, Sphenodiscus, Exogyra, Inoceramus Reference: http://txfossils.com/Txfossils.html Link to comment Share on other sites More sharing options...
abyssunder Posted June 22, 2016 Share Posted June 22, 2016 In my thought, there is a beautiful geological ensemble, what Mother Nature can give us from eons. " 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...
JohnBrewer Posted June 22, 2016 Share Posted June 22, 2016 I agree with the other two posters John Map of UK fossil sites Link to comment Share on other sites More sharing options...
Rockwood Posted June 23, 2016 Share Posted June 23, 2016 Good example of the way some rocks change in appearance when they weather. Seems likely that oxidizing iron is involved. Link to comment Share on other sites More sharing options...
tmaier Posted June 23, 2016 Share Posted June 23, 2016 A concretion can form from a fossil as the nucleus, but in this case I think this is an an iron concretion that has no fossil. This shows the many different colors that iron can take on. The iron atom has many states of oxidation and when it bonds with various anions this allows iron to have many different colors like brown, red, black, purple, yellow, etc. So all these colors are coming from one cation, the Fe ion. 1 Link to comment Share on other sites More sharing options...
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