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111 Views 5 Replies Last post: Jun 7, 2018 7:30 AM by Dr T RSS
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Jun 5, 2018 7:05 PM

Any Old Iron

Hi Team,

 

Attached are some pictures of rocks that I picked up on the foreshore at Kessingland Suffolk. They are Red/Brown and very grainy looking in the hand lens with some other larger pieces of reddish looking quartz mixed in and colour is not consistant. They are harder than steel and have a density of between 2.6 and 2.8. I think that they are Quartzite but they must have formed from some very iron rich sand?  Could they have been washed out of the Ferruginous layer at Pakefield or do you think that they have come from further afield? In cracks in a couple of the samples I have spotted some clear crystals which I thought might be sea salt but I have washed the rocks so salt would have disolved away I guess.

Any thoughts on these questions please gentlemen?

Regards

GrahamB

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  • Currently Being Moderated
    Jun 6, 2018 10:49 AM (in response to GrahamB)
    Re: Any Old Iron

    Hi - these are quartz/quartzite pebbles known as "Jasper"

     

    https://en.wikipedia.org/wiki/Jasper

     

    I expect they were brought into the area from much further afield during the Ice Ages

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  • Currently Being Moderated
    Jun 6, 2018 10:53 PM (in response to GrahamB)
    Re: Any Old Iron

    Essentially "Yes" - iron compounds range from orange to almost black but with a deep red colour, e.g. haematite (hematite) Fe2O3.  Jasper density ranges 2.5 to 2.9 so your values are spot on.  Harder than steel indicates silica - in this case chalcedonic silica

     

    http://geologylearn.blogspot.com/2016/12/jasper.html

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  • Currently Being Moderated
    Jun 7, 2018 7:30 AM (in response to GrahamB)
    Re: Any Old Iron

    They should tumble well - yes please start a new query for a different specimen with a new subject line.  It can get very cumbersome when people keep adding new specimens to the same thread and confusing if they use the same subject line for a new thread (can look like a duplicate)

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