Question About Petrographic Thin Section Problem

Paul bristolia at yahoo.com
Sun Jul 15 00:49:01 EDT 2007

Dear Friends,

Recently, a friend of mine prepared three thin
sections for me of some rock samples. However,
about a week after he finished them, it was
noticed that something had gone wrong with the
epoxy, which was used to cement the rock billets
to the glass slide. Over a period of a week, it
had started crystallize causing numerous linear
strings of crystals to form between the 0.3 micron
layer of rock and the glass slide and clouding
what should have been a clear cement. Needless
to say, there is now nothing, which can done
about these slides and as thin epoxy crystallizes,
they will be a total loss. (Note: this is the
second time a batch of this brand of epoxy has
caused this problem.)

However, he noticed this problem right after he
had glued another billet to the glass slide and
before he done any trimming of the billet in
preparation for grinding. Since the epoxy used
in mounting this slide will crystallize in time,
we concluded that there was not any point in
proceed any further with the preparation of
this thin section.

Is there any way which I can remove the glass
slide from the prepared billet in case of this
sample?

If I could, then I could grind off the epoxy
cement, polish the billet, and glue it again to
a glass slide and prepare a thin section using
good epoxy, which will not crystallize. Getting
the sample cost me considerable time and effort
and would be difficult to recollect. Thus,
finding a way to remove the glass slide, so I
can prepare a thin section whose epoxy will not
crystallize from this billet would be quite
helpful.

The sample consists of sandstone.

Any suggestions about how can remove the glass
slide and start over with this sample would
greatly appreciated.

Best Regards,

Paul

Need Recommendations for Petrographic Thin Section Maker

Paul bristolia at yahoo.com
Thu Mar 29 14:45:50 EDT 2007

Dear list members,

I need a number of petrographic thin sections made
for a project. Unfortunately, the petrographic thin
section lab, which I used has gone out of business.

Can anyone recommend, off list if desired, one or
more petrographic thin section lab(s), who make
quality standard petrographic thin sections?

Yours,

Paul
Baton Rouge, LA

what is the world standards for petrographical preparations (polarization microscopy)

Paul H bristolia at yahoo.com
Thu May 27 20:44:16 EDT 2004

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
http://www.union.edu/PUBLIC/GEODEPT/COURSES/petrology/thinsections.htm
http://almandine.geol.wwu.edu/~dave/other/thinsections/
http://www.lpl.arizona.edu/~rhill/fossil/thnsect.html

Making Petrographic Thin Sections
http://www.uni-wuerzburg.de/mineralogie/links/tools/making.html

Rock-Forming Minerals in Thin Section
http://www.uwgb.edu/dutchs/petrolgy/thinsect.htm

Atlas of Rocks and Minerals Under the Microscope
http://www.geologynet.com/thins.htm

Igneous rocks in thin section
http://www.union.edu/PUBLIC/GEODEPT/COURSES/petrology/ig_minerals.htm

Minerals in thin sections
http://www.uni-wuerzburg.de/mineralogie/links/petrology/thinsection.html


>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
http://www.nationalpetrographic.com/

Their price list is at:
http://www.nationalpetrographic.com/thin_sections.htm

Their price are average for what thin sections cost.

Elton


>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...

Yours,

Paul
Baton Rouge, LA