crinoid Posted February 18, 2014 Share Posted February 18, 2014 Hi all These rocks found on the holderness coast, all in the same area are all of the same base substance which is a dull gray very fine grain rock however sometimes when i have seen them split open i have found them to contain a variety of fossils such as Ammonites and other anomalies. the majority of these usually contain a large core of a calcite like crystal which varies greatly in color(second picture). one fossil collector told me many years ago that they were called Strombolites and that is what i have referred to them as since. A google search for the word Strombolite brought up nothing visually similar. there is one particular specimen (the last picture and the one that is furthest left on the first picture) that has a somewhat unique feature, it is approximately 12inches (30cm) diameter and much heavier the others of a similar size, the most notably interesting feature however is the fact that it appears to have gold protruding out of the side of it or so it seems. The golden substance is most probably iron pyrite yet i have not ruled out he preferable possibility of ancient gold. Here are some photos let me know your thoughts. Kind Regards Ed Link to comment Share on other sites More sharing options...
Auspex Posted February 18, 2014 Share Posted February 18, 2014 It appears that "Strombolite" is a crystalline mineral, rather than a diagenetic structure per se. I would simply call your structures concretions. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Wrangellian Posted February 18, 2014 Share Posted February 18, 2014 Yes, and Pyrite in that one. Link to comment Share on other sites More sharing options...
Herb Posted February 19, 2014 Share Posted February 19, 2014 I like the one that looks like a giant clam, and the item used for scale is great also. "Absence of evidence is not evidence of absence"_ Carl Sagen No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go. " I think, therefore I collect fossils." _ Me "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes "can't we all just get along?" Jack Nicholson from Mars Attacks Link to comment Share on other sites More sharing options...
painshill Posted February 19, 2014 Share Posted February 19, 2014 (edited) Strombolite isn’t an officially recognised mineral name but is sometimes applied by “new-agers” in the “crystal world” to a specific gem-quality variety of the mineral sturrite found in New Mexico. It’s dark purplish-blue and not an appropriate description of what you found. Actually what you have there are two quite different forms of concretion with different origins. The Holderness area has huge amounts of glacial till and “erratic” concretions as well as broken blocks of sedimentary rocks from further north are common finds. Typically Jurassic, from the Whitby and Speeton areas or Cretaceous from the North Sea beds. The two middle ones are septarian and have a mineralogical origin that may have commenced with organic decay, buy they won’t be fossiliferous. The left and right items are more typical sedimentary concretions that may well have remnant fossils as a nucleus. Those are indeed pyrite crystals (or pyrite pseudomorphs) around the edge in the final close-up picture. Pyrite around a ridge on a sedimentary concretion is often a good sign of a fossil origin, in that decomposing organic material generates reactive sulphurous gases that may well lead to iron sulphide formation. Edited February 19, 2014 by painshill 3 Roger I keep six honest serving-men (they taught me all I knew);Their names are What and Why and When and How and Where and Who [Rudyard Kipling] Link to comment Share on other sites More sharing options...
Wrangellian Posted February 19, 2014 Share Posted February 19, 2014 Maybe the word was supposed to be 'Thrombolite'? (which is also not applicable to these, I was just wondering if that was actually the word given) Link to comment Share on other sites More sharing options...
Scylla Posted February 20, 2014 Share Posted February 20, 2014 Aw man! Now I'm thinking of Stromboli and its making me hungry. Those are pretty decent pyrite crystals there. These don't look like stromatolites, but the word sounds similar. Link to comment Share on other sites More sharing options...
Auspex Posted February 20, 2014 Share Posted February 20, 2014 He might have meant "stromatolite" (which these are not). "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Scylla Posted February 20, 2014 Share Posted February 20, 2014 He might have meant "stromatolite" (which these are not). That's what I said Link to comment Share on other sites More sharing options...
Auspex Posted February 20, 2014 Share Posted February 20, 2014 That's what I said So you did! "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Scylla Posted February 20, 2014 Share Posted February 20, 2014 Great minds... and us Link to comment Share on other sites More sharing options...
Wrangellian Posted February 21, 2014 Share Posted February 21, 2014 True, Stromatolite might have been meant. Link to comment Share on other sites More sharing options...
RichW9090 Posted February 21, 2014 Share Posted February 21, 2014 I suspect the are Stromboli - they've been served with a nice wine, eh? The plural of "anecdote" is not "evidence". Link to comment Share on other sites More sharing options...
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