Hello Mark,
Go to Jim Tobin's article on Making Thin Sections in the
current issue of the on-line meteorite magazine, the Meteorite
Times:
http://www.meteoritetimes.com/
Click on the link "Jim's Fragments"
The color you see are produced by passing light through two
crossed polarizing filters with a very thin-cut slice (0.03 mm) thick between
them. How this works is explained in Richard Norton's series (see the
current issue of METEORITE magazine) for Aug. 2002. http://www.meteor.co.nz/
Making thin sections is a detailed process; to do it
properly one has to be sure the section is UNIFORMLY thick over the entire
piece, and that the thickness remains constant. This is done by checking
what is called birefringence as light passes through the polarizers
and the thin slice. Different minerals will show up as different colors,
and these change by rotating the polarizers relative to each other.
Usually the birefringence of light through olivine grains is used to check for
proper thickness in determining the proper thickness of the
thin-section.
The two articles, the first on how you may learn to make them
yourself, and the latter on the theory behind it, should give you the necessary
background to see how it all works.
Ron Hartman
Ron
R. N. Hartman
METEORITES and MEMBRANE SUSPENSION BOXES
[EMAIL PROTECTED]
www.meteorite1.com
[EMAIL PROTECTED]
www.membranebox.com
Mailing address:
The R. N. Hartman Collection
METEORITES
P.O. Box 94
Walnut, CA 91788-0094 (U.S.)
----- Original Message -----
From: Morawski, Mark <[EMAIL PROTECTED]>
To: Meteorite-List@Meteoritecentral. Com <[EMAIL PROTECTED]>
Sent: Thursday, August 15, 2002 5:23 AM
Subject: [meteorite-list] How to cut "thin
sections"
Good Morning list.
I am a beginning collector, and am wondering what is the technique for cutting the beautiful thin sections sometimes seen on EBay, I have a fair bit of lapidary equipment, but rather than trial and error, if there is a "proven methodology" I would appreciate it.
Thanks
-Mark-
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