Thin
Section Making
Thin
Section MakingAtlas of Rocks and Minerals
Under the Microscope
How Thin Sections are Made
Thin sections are thin slices of a rock or mineral specimen mounted on a microscope slide for examination under a polarising (petrological) microscope. The sections are made in a laboratory using equipment similar to the following:
6-8" Motorized Flat Lap
with 240# to 320# Diamond Lap
6-10" Motorized Diamond Saw
Glass Microscope Slides
Clear Epoxy Glue
Specialized laboratories have a lot more equipment for high volume work and specialized applications, such as polishing.
A thin section is made in the following way:
1. A thin slice of a rock or mineral specimen is cut on the diamond saw and trimmed to fit onto a glass microscope slide
2. The slice is glued to the microscope slide with clear 5 minute epoxy or similar glue
3. The slide is mounted in a special holder and ground on a diamond lap
4.When a thickness of 0.03mm is reached the section is complete and ready for examination under the microscope. The thickness of the section is usually measured with a digital micrometer or estimated by sight. With experience, a good estimation can be made by visual examination of the section and final checking with a microscope.
5. A cover slip is sometimes placed on the mount to protect the specimen.
