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petrographic polarizing microscopes review (old models)
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Author:  cascaillou [ Thu Dec 16, 2010 3:32 pm ]
Post subject:  petrographic polarizing microscopes review (old models)

http://www.microscopy-uk.org.uk/mag/ind ... polar.html

powerful identification tool for rocks and minerals (working from thin rock section or mineral powder). Not that easy to use (theory+practice needed)

Author:  Barbra Voltaire, FGG [ Fri Dec 17, 2010 12:01 am ]
Post subject:  Re: petrographic polarizing microscopes review (old models)

It is my understanding, most universities in the US do not even teach optical mineralogy anymore. :(
Thin sections, sadly, are heading in the same direction as the typewriter.

Author:  Brian [ Fri Dec 17, 2010 2:05 am ]
Post subject:  Re: petrographic polarizing microscopes review (old models)

We have no course focused solely on optical mineralogy, but optical techniques are a topic covered in the mineralogy course. We have the petrographic microscopes and case upon case upon case of thin-sectioned rocks. We even have the saw to cut the thin sections. The mineralogy course has a lab component, so the students do get exposure to the optical techniques.

Author:  Barbra Voltaire, FGG [ Fri Dec 17, 2010 11:20 am ]
Post subject:  Re: petrographic polarizing microscopes review (old models)

I'm glad to hear it.

I'm a member of the MSA boards and I hear a lot of complaining about the fact that thin sections are simply not as revered as they once were, when I was a lass. :)

I guess the sophistication of other methods of identification have played a large part. Although, I see nothing as cost effective as a thin section.

Author:  G4Lab [ Fri Dec 17, 2010 2:04 pm ]
Post subject:  Re: petrographic polarizing microscopes review (old models)

Perhaps there will be a "rediscovery" of them. In an analogous way the making of thin biological sections which used to be taught even in better high schools, but certainly at any university biology department, went out of fashion for a few decades, only being taught at programs specifically aimed at clinical pathology labs.

But now the U where I work has hired a guy who describes himself as a Histologist and he had me overhaul all the old microtomes in the store room and the other day I walked into his lab and it was like a bunch of kids dyeing Easter eggs. About ten students staining sections that they had cut. I had never seen such a thing even when I was an undergraduate about the same time Barbra was. (although I never used a microtome I DID use an ULTRA microtome for the transmision electron microscope as an undergrad)

Both techniqes are so basic that they can't be allowed to be forgotten.

Author:  cascaillou [ Sat Dec 18, 2010 12:33 pm ]
Post subject:  Re: petrographic polarizing microscopes review (old models)

I have yet to learn the basics of the polarizing mirocoscope but it sounds like a great tool. I'm not much interested in thin rock sections (good thing considering that the cutting equipment is expensive). Actually I'm mainly interested in the identification of rough minerals in powder form and I was told that one needs much less than one cube millimeter of powder to achieve identification, so I wouldn't really qualify this technique as destructive. The one thing that stops me from experimenting with it is the price of those scopes.

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