Friday, March 18, 2011

Old-school optical petrology question

Dear Readers,
What are the standard sizes for petrographic thin sections? Americans may answer in inches, of that is their standard. metric sizes would also be appreciated.

I seem to recall 1x2 inch and 1x3 inch from my days of youth, but I can't find any written evidence of that.



Alke said...

I'd say the ones we used in our optics classes were 2x4 cm or 2x5 cm. My office is on the same floor as the classroom. If my key fits, I can take a look tomorrow.
The thin sections I made for my diploma mapping (all sediments) were square (3x3 cm?) I think.

Unknown said...

I want to say ~3/4" x 1.5" (~1.9 cm x 3.8 cm)

I know that they were narrower than 1" but thicker than 0.5"

C W Magee said...

Thanks guys. If you could also mention what country you are in, that would be great too.

Unknown said...

midwest U.S.

Schenck said...

Is there actually a text-book standard? One dimension is determined by the width of the slide, and the other can really be a variety no? I feel like most I saw as an undergrad in the eastern US were square though. But you can't always guarentee that the chip the section is made from is going to be 1x2 or 1x3 inches or anything like that.

As far as thickness, which someone else brought up, isn't that really the only important dimension? Its the one that makes it a thin section that light can pass through (at 30 microns)

Also, some of the people I work with work on meteorites, and for some reason those sections are often mounted on round slides. Usually they're looking at thin sections, but in an SEM (they also don't have coverslips), and a regular slide would be oversized for most SEM mounts, so maybe thats why those are round.

C W Magee said...

I should have clarified- it is actually the slide size that I am after, not the size of the section glued to the slide. It is a common complaint of geologists that their slide don't fit into analytical instruments, but if the slide size is not very standardized, then it becomes a lot harder for instrument manufacturers to design something that will accommodate them..
Hypothetically speaking, of course.

Ron Schott said...
This comment has been removed by the author.
Ron Schott said...

The petrographic thin section slides in my office all measure 4.6cm by 2.7cm. To the best of my knowledge they all originate from the USA.

Alke said...

The ones in the classroom next to my office measure 2.7x4.8 cm.
I work in Germany.