Cabochon stone cutting

Stone cutting class in trade school during the first year.

1st picture

Top left: We started with big chunks of rocks that we could choose from. The rocks had different hardnesses (marble, quartz and granite), so we had to try them all.
Top middle: Sawing the rocks carefully into thin slabs. Steady and slow, because the stones chip easily near the end. The stone saw doesn’t cut soft tissue, but I still wouldn’t stick my finger near it 😀
Top right: Drawing the shape on the stone using a template. The circle is the final size, the outer lines need to be sawed off.
Bottom left: Rough shape after sawing. From left to right: granite, green marble and Carrara marble (soft stones), epidote quartz and snowy quartz (hard stones).
Bottom middle: The polishing machine. The first two on the left (80 and 230) are for sanding and the the rest (280, 600, 1200, 14000) are for polishing. You go through them all and wash the stone and hands thoroughly between each step.
Bottom right: Starting to smooth out the rough edges. Keep moving the stone the whole time or it ends up faceted.

2nd picture

Top left: After sanding the stones to the correct shape, they are attached to sticks for easier handling. We tried super glue (left), stone putty (middle) and thermo wax (right). You shouldn’t use super glue on quartz stones, because the glue goes through the cracks on the stone and gives it a yellow tint.
Top middle: Sanding the first facet on the stone. Keep sanding until you reach the desired cabochon shape.
Top right: Finished sanding. From left to right: granite, snowy quartz, green marble, epidote quartz and Carrara marble. The Carrara marble was clearly softer than I expected, but I still decided to finish it.
Bottom left: Tin oxide for final polishing.
Bottom middle: After polishing the stone with a felt buffing wheel.
Bottom right: Sanding the bottom. You can also do this on a water emery sheet. Facet the bottom edge as well, so the stone doesn’t chip when setting it.

I cut more stones after this class and made a pendant and a ring.

Materials: Granite, Carrara marble, green marble, snowy quartz, epidote quartz
Date: January 2013