Author Topic: Rock specimen - identification please?  (Read 536 times)

Online Moose

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Rock specimen - identification please?
« on: March 05, 2020, 07:29:08 pm »
Found in a Castleton swallet cave today. I'm really not sure what this is..... anyone wish to enlighten me

Offline AR

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Re: Rock specimen - identification please?
« Reply #1 on: March 05, 2020, 08:21:31 pm »
That looks like Goethite - fairly common in the Peak.
Dirty old mines need love too....

Online Moose

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Re: Rock specimen - identification please?
« Reply #2 on: March 05, 2020, 08:27:47 pm »
Just read up on that and I'd go along with that identification.

Thanks.

Offline aricooperdavis

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Re: Rock specimen - identification please?
« Reply #3 on: March 05, 2020, 08:58:36 pm »
Is there a rock/mineral identification thread, or can we start one?

I found a lovely pebble on the beach at Porthtowan during one of the recent storms, with lustrous brass coloured flecks (pyrite?) and the quartz on the base has a tessellating hexagonal honeycomb pattern. Poorly lit photos attached to this post.

Offline braveduck

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Re: Rock specimen - identification please?
« Reply #4 on: March 05, 2020, 09:30:48 pm »
I think the blue/grey end is Gabbro .

Offline Pitlamp

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Re: Rock specimen - identification please?
« Reply #5 on: March 06, 2020, 12:39:01 pm »
looks like a bit of limestone fault breccia - but, as ever, very difficult to tell from a photo alone.

What's it's density like (i.e. does it feel heavy for its size)?

Is it very hard or it it crumbly?

Any reaction with hydrochloric acid (I realise you may not have had chance to try that)?

Does the edge look at all laminated (suggesting a sedimentary rock)?

 

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