Making a thin section, as described here, involves starting with a large limestone-like mineral specimen, such as fossil coral, and from it producing a thin slice section of a specific section of it attached to a labled glass slide.

It needs to be prepared thin enough to be viewed as a transparency with an optical microscope, and also with a polarized light petrographic microscope.

The thin section slide needs to be identified and be accessable in a database.

The general steps in the making of a thin section are:

A process checksheet is prepared for the thin section, to track the process since several specimens are usually prepared in parallel, over several days or weeks to complete, at least requiring epoxy cure time.

The specimen to be thin sectioned is bulk sawn several times so as to expose the desired plane for examination, and chip sized to fit on a glass slide's area.

The chip face is then polished, cleaned, dried, and attached to a glass slide with epoxy. The slide identification is engraved with a carbide tip scribe, before the chip is epoxied to it.

Using the setup called the "Thin Section Laboratory", shown in photo to the right, the chip is further sectioned and ground to almost the desired thickness of about 40 microns. It is then polished on a glass plate with fine grit, to 1000 grit smoothness.

The completed thin section is then physically stored and its data is placed into a database for recovery when needed.

This is a volunteer's Work In Progress, version 2 by Jim Cline, updated 20040408, for LACNHM Invertebrate Paleontology