Lapidary refers to the art of cutting and polishing gemstones. It’s a time-consuming and laborious procedure because gemstones are extremely hard, with the majority being harder than steel. Gemstones can be quite precious, with top-quality rubies and sapphire fetching hundreds of dollars per carat. Working with pricey materials that are readily destroyed is also stressful.
The first stage of gemstone cutting does not entail any cutting at all. Rather, it entails assessing the information and deciding how to continue. Because judging a raw stone is more difficult than analysing a finished diamond, it needs a lot of practise and a good eye. The first step is to assess whether the material is translucent and clean enough to cut a faceted gem; if it isn’t, a cabochon will be carved instead. If the stone is facetable, the cutter must choose which section of the rough stone to facet and what form to cut.
Both economics and aesthetics must be considered by the gem cutter. The cutter aims to keep as much of the rough stone as possible because gem-quality material is scarce and valuable. This is why so many stones are cut as ovals: gems found in alluvial deposits tend to be oval in shape, as they are produced over thousands of years by the action of water.
The rough stone is prepared to the approximate shape on a silicon carbide wheel once the shape is determined and the material chipped away. For the enormous table facet on the crown of the diamond, one side of the stone is normally cut with a flat surface.
After that, the stone is ready for faceting. The gem is first bonded to a little stick known as a dop, which is made of wax that melts at a high temperature. The gem is then held at a precise angle against a horizontal cutting wheel called a lap, with the pavilion (bottom half) of the stone being the first to be cut. Modern faceting machines feature mechanical arms that allow for extremely precise control of faceting angles, but in the hands of a skilled operator, simpler devices can also provide excellent results.
After all of the facets have been cut, polishing begins, which is more of an art than a science. The goal is to obtain a mirror-like quality while also removing any small scratches that may have been left over after the grinding procedure. Diamond or corundum grit, tin oxide, cerium oxide, and chromium oxide are among the polishing compounds utilised. Expert polishers know how to produce the greatest results by varying the lap speed and pressure, as well as the consistency of the polishing chemical.
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