Production of Thin Sections


Lab photographs from the JSC Rock Laboratory.
Click here for detailed instructions for the production of thin sections.

Step 1: Use the slab saw for large samples.
Be sure the rock is secured firmly in the clamp.


Step 2: Use the trim saw and cutting guides to cut rocks to an appropriate size.
Hold the rock firmly down on the aluminum plate.

Step 3: Use the lap polisher to remove scratches
in the rock chip left by the trim saw; rotate the rock chip
and slide it back and forth across the entire surface.


Step 4: Use a slurry of #600 aluminum oxide grit on a #600 glass plate to polish the rock chip;
use a figure-eight or circular motion across the entire glass plate.


Step 5: The rock chip is appropriately polished when the surface is smooth
and has a continuous, even reflection when viewed toward a light source.
Hold the chip parallel to the light source.


Step 6: Thoroughly wash the chip and dry it
in a muffle furnace (at 100°C) for at least 18 hours.

Step 7: Glue the rock chip to a frosted slide;
use a pencil eraser to push air bubbles to the edge of the slide.


Step 8: Place the chip and slide into the bonding jig;
be sure the chip is aligned with the edge of the slide.

Step 9: Use a razor blade to remove excess glue on the edges and back of the slide.


Step 10: Number slide with a pencil on frosted side
and use a diamond awl on the smooth side.


Step 11. Use the cutoff saw (left) to cut the chip off of the glass slide. Then use the grinding wheel (right) to remove the sample at two microns per pass. Thin the sample to 40 microns.


Step 12: Each specimen must be hand-ground to 30 microns;
use a slurry of #600 aluminum oxide grit on #600 glass plates.

Step 13: Use polarized light to check thickness;
the goal is exactly 30 microns.


Step 14: A finished thin section.
The "peace dove" is quartz (with the gypsum plate inserted).

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