What is this small black piece of stone?

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Offline lukasjacobs

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What is this small black piece of stone?
« on: 19/10/2015 21:59:49 »
please id this.
« Last Edit: 20/10/2015 00:28:19 by chris »

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Offline RD

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Re: What is this small black piece of stone?
« Reply #1 on: 20/10/2015 01:28:37 »

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Offline lukasjacobs

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Re: What is this small black piece of stone?
« Reply #2 on: 20/10/2015 04:52:46 »
It is non magnetic.Have not been cut etc. in any way.It looks like red sand in between the crystals,acid in lab could not clean it up.v

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Offline chris

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Re: What is this small black piece of stone?
« Reply #3 on: 21/10/2015 11:30:52 »
It's certainly fascinating, although I don't know what it is; can you tell us a bit more about the context in which it was found?
I never forget a face, but in your case I'll make an exception - Groucho Marx

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Offline Bass

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Re: What is this small black piece of stone?
« Reply #4 on: 24/10/2015 19:46:05 »
Cubic form of the crystals indicates this is a pyrite nodule. I assume it feels a bit heavier than a regular garden stone of the same size.  Black color is probably goethite oxidizing from the pyrite.
Old enough to have a grandson
Slow enough to study rocks
Thirsty enough to find a pub

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Offline Bill S

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Re: What is this small black piece of stone?
« Reply #5 on: 25/10/2015 17:52:25 »
Have you tried scratching a crystal to check the colour of the streak?

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Offline chris

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Re: What is this small black piece of stone?
« Reply #6 on: 25/10/2015 22:04:59 »
this is a pyrite nodule.

What does this mean it's made of? Is it an iron sulphide?
I never forget a face, but in your case I'll make an exception - Groucho Marx

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Offline Bass

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Re: What is this small black piece of stone?
« Reply #7 on: 03/11/2015 23:17:07 »
Yes, iron sulfide (FeS2)
Old enough to have a grandson
Slow enough to study rocks
Thirsty enough to find a pub

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Offline chiralSPO

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Re: What is this small black piece of stone?
« Reply #8 on: 04/11/2015 03:30:45 »
I'm pretty sure it's a Borg Sphere, you might want to be careful with it if you don't want to get assimilated...

http://employees.csbsju.edu/rsorensen/modelcitizen/trekships/borg/borgsphere.jpg