How Does Gemstone Polishing Work?

Science hasn’t yet explained how gemstone polishing works. In the early half of the 20th century, there were two competing theories.

Newton, the guy famous for watching apples fall, came up with the scratch theory. It postulates that scratches smaller than a wavelength of light are no longer visible. When polishing with very fine diamond, this is likely to be the case, but this theory hasn’t been proven.

Another fellow named G.T. Beilby came up with the theory that, at a molecular level, there’s melt and flow. This has been disproved a number of times. However, if this doesn’t hold true, then how do we account for gems being polished by much softer abrasives? Colloidal silica has an abrasive with a hardness of 4. However, it polishes gems up to 9 in hardness. There’s no scientific explanation for how this happens.

Although science has made some advances in understanding how polishing works for glass and some minerals, the overall gemstone polishing process remains a mystery to be solved. For now, however, we’re going to focus on the practical matter of gemstone polishing.

Gemstone Polishing: General Considerations

Before discussing gemstone polishing equipment and techniques, let’s go…