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Author Topic: What have I found here?  (Read 2315 times)

Offline ShaneG

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What have I found here?
« on: 06/09/2012 17:23:38 »
Hello and thank you for visiting my post. I am new here and what brought me is peoples willingness to help identify rocks.

As a kid I my head was always down. Partly to being a scrawny little guy that was all arms and legs so I was kinda shy. The other was I always had an eye out for interesting rocks, especially after a rain.
Oddly enough I've never really learned to identify them. I know my quartz and the odd agate or jasper.

So without further introduction here an interesting rock I found. It is a rather large stone with this interesting vein in it.  I can tell the quartz easy enough but it's the black formations below it. The odd thing was when I took the picture with the LED flash the black turned green.

Any ideas?






 

Offline ShaneG

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Re: What have I found here?
« Reply #1 on: 06/09/2012 17:32:01 »
A closer look can be found here. Sorry the first pictures didn't show this clearly enough.

newbielink:http://homecnchobby.net/matrixish_opt.jpg [nonactive]
 

Offline Bass

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Re: What have I found here?
« Reply #2 on: 06/09/2012 21:20:15 »
I suspect the black xtals are specular hematite (a form of iron oxide).  If you can rub the black xtals on a piece of white porcelain- if it leaves a red streak it is hematite, a greenish-black streak is pyrite.
 

Offline RD

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Re: What have I found here?
« Reply #3 on: 07/09/2012 02:12:34 »
... The odd thing was when I took the picture with the LED flash the black turned green.




Fluorescence is a possibility, as camera flash can emit UV light ...

Quote
Flashtubes produce very intense flashes, often faster than the eye can register, and may not appear as bright as they are. Quartz glass will transmit nearly all of the long and short wave UV, including the germicidal wavelengths, and can be a serious hazard to eyes and skin.
https://en.wikipedia.org/wiki/Flashtube#Safety
« Last Edit: 07/09/2012 03:15:55 by RD »
 

Offline ShaneG

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Re: What have I found here?
« Reply #4 on: 07/09/2012 19:18:34 »
Great thanks. I went back to the spot and took a knife to it to see how hard it was. It was easy to break apart.

I have a few other interesting oddities but I don't have the pictures of them with me.
 

Offline Bill S

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Re: What have I found here?
« Reply #5 on: 15/10/2012 22:14:53 »
ShaneG, specular hematite is certainly a possibility, but after looking at the pic in your second post, I would say it might be worth approaching it with a magnet in case it is magnetite.
 

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Re: What have I found here?
« Reply #5 on: 15/10/2012 22:14:53 »

 

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