Samwise Posted November 10, 2015 Share Posted November 10, 2015 Hey guys! I'm completely new here and am loving the look of the forum already. I'm quite a novice but looking to improve my knowledge! I was just wondering what you thought of this? Is it pyrite? Just wondering if it is worth trying to crack it open. It weights a 1kg and has a density of around 4800. Cheers! Sam Link to comment Share on other sites More sharing options...
abyssunder Posted November 10, 2015 Share Posted November 10, 2015 (edited) Welcome to the Forum! If I'm not wrong I think you have a marcasite nodule specimen, white pyrite, with a different (unstable) crystal structure than pyrite, with tabular crystals; having specific gravity equal to 4.88 gm/cc. Edited November 10, 2015 by abyssunder 1 " 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...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 Welcome to the Forum! If I'm not wrong I think you have a marcasite nodule specimen, white pyrite, with a different (unstable) crystal structure than pyrite, with tabular crystals; having specific gravity equal to 4.88 gm/cc. Excellent! Thank you very much for your help.. I would never have got there. I'll do some research into what you said so I can understand it all Is it worth cracking open? / any ideas of the best way to do this? Cheers, Sam Link to comment Share on other sites More sharing options...
Raggedy Man Posted November 10, 2015 Share Posted November 10, 2015 Welcome to the forum! I hope you enjoy this invaluable tool. Best regards, Paul ...I'm back. Link to comment Share on other sites More sharing options...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 Welcome to the forum! I hope you enjoy this invaluable tool. Best regards, Paul Thanks Paul, Already really enjoying looking through the threads. I've got a few fossils which i'll upload too. Cheers, Sam Link to comment Share on other sites More sharing options...
jpc Posted November 10, 2015 Share Posted November 10, 2015 Welcome from Wyoming. I am intrigued by your photo ... do you work on the North sea? Oil? Link to comment Share on other sites More sharing options...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 Welcome from Wyoming. I am intrigued by your photo ... do you work on the North sea? Oil? Aha not far off, I work on oil and gas exploration vessels. That photo was taken in the Arctic but most of my work is in the North sea. - Been to the gulf a few times.. a lot less cold. Link to comment Share on other sites More sharing options...
Ludwigia Posted November 10, 2015 Share Posted November 10, 2015 Welcome to the forum. Where did you find that nodule? Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 Welcome to the forum. Where did you find that nodule? Hey, thanks for the warm welcome. Good question - my Grandad gave it to my Dad a very long time ago and we have forgotten where from. It is most likely that he found it in the Thames as he used to work on excavations in central london. Worth opening - I assume it is unlikely there is a fossil, especially as london is clay? Link to comment Share on other sites More sharing options...
Ludwigia Posted November 10, 2015 Share Posted November 10, 2015 I'd leave it as is. Maybe polish it up a bit with a wire brush. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
frankh8147 Posted November 10, 2015 Share Posted November 10, 2015 Yep, don't break it open. I would refer to old posts regarding pyrite preservation; I have seen a lot of my pyritized fossil wood deteriorate from 'pyrite disease' so take the proper precautions. If you really like it, look up the article on this forum about that or find an air tight container (it worked for me but I would highly recommend that article). -Frank Link to comment Share on other sites More sharing options...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 I'd leave it as is. Maybe polish it up a bit with a wire brush. Yep, don't break it open. I would refer to old posts regarding pyrite preservation; I have seen a lot of my pyritized fossil wood deteriorate from 'pyrite disease' so take the proper precautions. If you really like it, look up the article on this forum about that or find an air tight container (it worked for me but I would highly recommend that article). -Frank Thanks guys, there I was with my hammer ready to go.. Still, as it's my first real fossil i'm tempted to break it anyway just to see... Will have a look through the preservation posts too Link to comment Share on other sites More sharing options...
frankh8147 Posted November 10, 2015 Share Posted November 10, 2015 Good call; I have a stream near me with a good amount of pyrite in it; I broke open hundreds of pieces but have only found one or two with good fossils in them so the odds are not in your favor on that one. Nice find! Link to comment Share on other sites More sharing options...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 Against all advice and good sense, curiosity killed the cat. I'm sure you will appreciate my excellent oil and gas health and safety attire.. So this is what I got... The photo doesn't really do the silver colour justice, it really looks great. If there is anything you guys can tell me more about it now it's opened that would be great. It has a strange centre... Link to comment Share on other sites More sharing options...
Auspex Posted November 10, 2015 Share Posted November 10, 2015 Classic pyrite/marcasite formation. "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...
Kosmoceras Posted November 10, 2015 Share Posted November 10, 2015 Very nice, that split well. I find these in the chalk sometimes. Now it is split open I would advise giving the newly exposed surface a coat of paraloid, all mine have started to react soon after splitting them open. Link to comment Share on other sites More sharing options...
abyssunder Posted November 10, 2015 Share Posted November 10, 2015 Very nice! Thank you for the update! I appreciate your decision to crack it open. " 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...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 Yep put a layer on it, unfortunately it seems to have dulled it. Still.. happy with the clean cut (although a bit confused by the texture at the very centre). Thanks for all the advice guys. I've got a few old pieces that my Granddad bought that I will put up asap! Link to comment Share on other sites More sharing options...
abyssunder Posted November 10, 2015 Share Posted November 10, 2015 https://www.google.com/search?q=marcasite+nodule&biw=1360&bih=612&tbm=isch&tbo=u&source=univ&sa=X&ved=0CB4QsARqFQoTCIbrterphskCFclUFAodTkEPGg#imgrc=I5Ir5nbuH0Fg2M%3A " 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...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 https://www.google.com/search?q=marcasite+nodule&biw=1360&bih=612&tbm=isch&tbo=u&source=univ&sa=X&ved=0CB4QsARqFQoTCIbrterphskCFclUFAodTkEPGg#imgrc=I5Ir5nbuH0Fg2M%3A Ha i've been looking for a similar one for a while! Doesn't seem to be much of a market for them so I guess that's why I struggled.. Still who cares if it has no monetary value. It's my first! Link to comment Share on other sites More sharing options...
Ludwigia Posted November 10, 2015 Share Posted November 10, 2015 So the inquiring scientific mind wins out! Nice result. I used to have tons of these things when I was collecting minerals. There was a quarry not far from here which was full of them. The stuff in the center was probably originally organic material which sulfate reducing bacteria ingested, digested and regurgitated and with their help marcasite crystals were created which grew radially outward, forming the concretion. It's unfortunate that they oxidize so quickly, losing some of the original silvery sheen. 1 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
abyssunder Posted November 10, 2015 Share Posted November 10, 2015 You are correct! Not the monetary value is in the front of all, but the feeling that you makes happy when you find something like this. Unfortunately, I've never found in Romania such specimen. " 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...
Samwise Posted November 10, 2015 Author Share Posted November 10, 2015 (edited) So the inquiring scientific mind wins out! Nice result. I used to have tons of these things when I was collecting minerals. There was a quarry not far from here which was full of them. The stuff in the center was probably originally organic material which sulfate reducing bacteria ingested, digested and regurgitated and with their help marcasite crystals were created which grew radially outward, forming the concretion. It's unfortunate that they oxidize so quickly, losing some of the original silvery sheen. Fantastic bit of info! Really interesting and explains a lot of how it would have formed. Do you know how old these things are? I guess you'd need location which I don't need... I'd hazard a guess at Cretaceous period but a very uneducated one You are correct! Not the monetary value is in the front of all, but the feeling that you makes happy when you find something like this. Unfortunately, I've never found in Romania such specimen. Ahh i'm sure you have better things than me Edited November 10, 2015 by Samwise Link to comment Share on other sites More sharing options...
Ludwigia Posted November 10, 2015 Share Posted November 10, 2015 (edited) Fantastic bit of info! Really interesting and explains a lot of how it would have formed. Do you know how old these things are? I guess you'd need location which I don't need... I'd hazard a guess at crustaceous period but a very uneducated one These things can be of all ages, young or old, so you can't really say how old yours is, since you don't know for sure where it came from. If it does come from the London clay, then it's Eocene in age and between 49 and 56 million years old, which is relatively young, geologically speaking. The main thing is that they build in sediments and mainly where there were anaerobic conditions at the time they were formed (lack of oxygen). Edited November 10, 2015 by Ludwigia 1 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
abyssunder Posted November 10, 2015 Share Posted November 10, 2015 (edited) I agree! Just a few remarks about :MARCASITE (cited from http://www.theodora.com/encyclopedia/m/marcasite.html), "a mineral with the same chemical composition as pyrites, being iron disulphide FeS2, but crystallizing in the orthorhombic instead of in the cubic system. The name is of Arabic origin and was long applied to crystallized pyrites (q.v.); it was restricted to the present species by W. Haidinger in 1845. The mineral was known to G. Agricola in 1546 under the names Wasserkies or Weisserkies and Leberkies, and it has been variously known as white pyrites, hepatic pyrites, lamellar pyrites, radiated pyrites (German Strahlkies) and prismatic pyrites. The orthorhombic form of the crystals, as distinct from the cubic form of pyrites, was recognized by Rome de 1'Isle in 1772, though later R. J. Hairy considered the crystals to be only distorted cubic forms.The crystals are isomorphous with mispickel, but only rarely are they distinctly developed and simple (fig.). Usually they are twinned on a prism plane, M, producing pentagonal stellate groups of five crystals; twinning on the plain g, in which the crystals intercross at angles of nearly 60°, is less common. This frequent twinning gives rise to characteristic forms, with many re-entrant angles, to which the names "spear pyrites" and "cockscomb pyrites" are applied.The commonest state of aggregation is that of radially arranged fibres, the external surface of the mass being globular, nodular or stalactitic in form.Apart from crystalline form, the external characters of marcasite are very similar to those of pyrites, and when distinct crystals are not available the two species cannot always be easily distinguished. The colour is usually pale bronze-yellow, often rather lighter than that of pyrites; on freshly fractured surfaces of pure marcasite the colour is tin-white, but this rapidly tarnishes on exposure to air. The lustre is metallic and brilliant. The streak is greyish or brownish-black. The hardness (6-62) is the same as that of pyrites, and the specific gravity (4.8-4.9) as a rule rather less. Arsenical varieties of marcasite, containing up to 5% of arsenic, are known as lonchidite and kyrosite.Marcasite readily oxidizes on exposure to moist air, with the production of sulphuric acid and a white fibrous efflorescence of ferrous sulphate, and in course of time specimens in collections often became completely disintegrated. In nature it is frequently altered to limonite with the separation of native sulphur. Marcasite is thus the less stable of the two modifications of iron disulphide. Many experiments have been made with a view to determining the difference in chemical constitution of marcasite and pyrites, but with no very definite results. It is a noteworthy fact that whilst pyrites has been prepared artificially, marcasite has not.Marcasite occurs under the same conditions as pyrites, but is much less common. Whilst pyrites is found abundantly in the older crystalline rocks and slates, marcasite is more abundant in clays, and has often been formed as a concretion around organic remains. It is abundant, for example, in the plastic clay of the Brown Coal formation at Littmitz, near Carlsbad, in Bohemia, at which place it has been extensively mined for the manufacture of sulphur and ferrous sulphate. In the Chalk of the south-east of England nodules of marcasite with a fibrous radiated structure are abundant, and in the Chalk Marl between Dover and Folkestone fine twinned groups of "spear pyrites" are common. The mineral is also met with in metalliferous veins, though much less frequently than pyrites; for example the "cockscomb pyrites" of the lead mines of Derbyshire and Cumberland. (L. J. S.)" Edited November 10, 2015 by abyssunder " 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...
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