Specimen preparation requirements

Sample Sizes and Labelling

Optimal sample sizes include: round sample mounts 25.4 mm (1.0 inch) in diameter and ideally less than 4.4 mm (0.173") in height, or thin sections with dimensions of 46 x 27 x 1.27 mm (1.81 x 1.06 x 0.05 inches).

Other sample sizes can be accommodated, but contact us to make sure your sample size is useable. The Thin Section Laboratory in Earth and Atmospheric Sciences is the primary source for excellent sample preparation.

A list of commercial thin section labs in Canada and the USA can be found here (this does not constitute an endorsement of these labs).

Labels on glass thin sections should be engraved permanently with a tungsten carbide scriber, as solvents may degrade indelible ink or painted labels.


Before analysis, the sample surface must be polished to better than 1 micrometer (no cover slips), and then coated with a thin film of electrically-conductive material (usually carbon; gold or other metals are also available). Carbon-coating takes time; please provide us with your sample(s) in advance. All of our standards are currently carbon-coated (~25 nm thickness).

Carbon-coat thickness is judged by interference colours shown by a simultaneously-coated brass surface (30, 25, 20 nm) following Kerrick et al. (1973).

Thinner carbon-coats can be performed at nanoFAB with the Leica ACE 600 coater (article).

No Stained/Dyed Samples

Following the advice of Dr. J. Fournelle (University of Wisconsin - Madison), thin sections that have been stained or dyed to distinguish phases such as carbonates or feldspars are not permitted for examination by the electron microprobes. 

Epoxy Resins

The University of Edinburgh NERC Ion Micro-Probe Facility discusses various epoxy resins at: