Could this crystal be volcanic glass?

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cliff taylor

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Could this crystal be volcanic glass?
« on: 15/06/2008 20:14:56 »
cliff taylor asked the Naked Scientists:

I found a crystal on a beach that looks like glass at where it is broke but has a mineral look on the sides that are not broke but I can cut glass with it but does not effect the stone.

What do you think?

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Offline Bass

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Could this crystal be volcanic glass?
« Reply #1 on: 16/06/2008 18:43:13 »
Quartz perhaps?
Old enough to have a grandson
Slow enough to study rocks
Thirsty enough to find a pub

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Offline chris

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Could this crystal be volcanic glass?
« Reply #2 on: 18/06/2008 08:14:42 »
What about obsidian (volcanic glass)? Where does that sit on Moh's scale?
I never forget a face, but in your case I'll make an exception - Groucho Marx

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Offline RD

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Could this crystal be volcanic glass?
« Reply #3 on: 18/06/2008 09:04:29 »
Quote
Obsidian has a glassy lustre and is slightly harder than window glass.
Though obsidian is typically jet-black in colour

http://www.britannica.com/eb/topic-424074/obsidian


« Last Edit: 18/06/2008 09:08:14 by RD »

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Offline thedoc

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Could this crystal be volcanic glass?
« Reply #4 on: 18/06/2008 13:13:27 »
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bill

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« Reply #5 on: 30/07/2015 23:17:31 »
crrrrrrrrrrrrrap