[meteorite-list] what is the world standards for petrographicalpreparations(polarization microscopy)
From: Adam Hupe <adamhupe_at_meteoritecentral.com>
Date: Thu May 27 21:33:46 2004
Hi Paul and List,
Some really high end preparation laboratories imbed quartz in the epoxy
around the specimen so that the process is more automated and uniform
thickness is achieved. This is an ingenious way to calibrate equipment
All the best,
----- Original Message -----
From: "Paul H" <bristolia_at_yahoo.com>
Sent: Thursday, May 27, 2004 5:44 PM
Subject: [meteorite-list] what is the world standards for
> E. L. Jones jonee at epix.net wrote:
> >I am also interested in the use of "quartz"
> >as index markers. This isn't in any of my
> >reference books. Are they attached to the
> >specimen and ground at the same time as the
> >thin section?
> No. The person grinding the thin section uses
> the bifringence of whatever minerals are
> present to judge the thickness of the thin
> section. Quartz is used as an index marker
> simply because, it is so common as to be
> present in most sedimentary, igneous, and
> metamorphic rocks. When it isn't present,
> a person uses whatever mineral happens to
> be in the thin section as an index.
> Some web pages are:
> Making Petrographic Thin Sections
> Making Petrographic Thin Sections
> Rock-Forming Minerals in Thin Section
> Atlas of Rocks and Minerals Under the Microscope
> Igneous rocks in thin section
> Minerals in thin sections
> >Another question I have. Is there a house
> >that specializes in preparation? Kinda of
> >like the $2 a carat faceting deals one can
> >get in Thailand?
> There are many places that specialize in making
> thin sections. Typically, a person gets what
> they pay for. A quick search using Google will
> find a number petrographic labs that make thin
> sections. If you are going to pay 5 to 50 dollars
> a gram for a meteorite, paying 15.00 dollars for
> a high quality thin section is the least of
> your costs.
> The people that use to make the thin sections for
> my research (and search for more shocked quartz)
> from samples in the Brushy Creek Carter is:
> National Petrographic Service, Inc.
> 5933 Bellaire Blvd., Suite 108
> Houston, TX 77081
> Their price list is at:
> Their price are average for what thin sections cost.
> >Roman Davidov wrote:
> >>Dear list members. Hello.
> >>My question is: What is the world standards for
> >>petrographical preparations. If I'm not mistaken
> >>in English it sounds like "THIN SECTIONS".
> Yes, as noted above, the term is "thin section".
> >To be more concrete I mean: form and sizes of
> >object glass (width,height,thickness);
> The glass slide of the standard thin section is
> 27 x 46mm (1" x 1 7/8"). Larger slides are produced,
> but size might vary according to the lab that
> prepares them. For example, National Petrographic
> has 38 x 75mm (1.5" x 3") and 50 x 75mm (2" x 3")
> size glass slides for larger size thin sections.
> >type of optical glue (we are using composition
> >named "Canadian Balsam");
> Hillquist A-B is used to glue slabs to slides.
> However, Canadium Balsam is the standard for
> attaching the coverslip. If you want to do any
> microprobe, etxching, or similar work, i.e. for
> identifying shocked quartz, the thin section needs
> to be finished by polishing and the coverslip
> left off.
> >linear sizes of object (I'm sure that thickness
> >is one to all of the world - 0.003 millimeters);
> >form and sizes of cover glass.
> The only requirement for the size of the object
> is that it is a few mm smaller than the size of
> the glass slide being used. The coverslip is
> larger than the specimen and smaller than
> the slide.
> The coverslips come in sizes, thicknesses, and
> optical character that are standardized for use
> in making thin sections. A person needs to talk
> with the people supplying the coverslips and
> get the technical specifications of what they
> are selling to see if they are suitable for
> thin sections.
> ...text deleted...
> Baton Rouge, LA
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Received on Thu 27 May 2004 09:17:10 PM PDT