Following on from my introduction to gemstones, here is a little information on cutting.
On a basic level stones are generally either cut with facets, or into cabochons, which have a flat back and normally a smooth surface.
Generally transparent gemstones are faceted, as those which are opaque don't reflect light internally in the same way. Harder stones are also generally used as scratches are more obvious on faceted stones.
Cuttings diamonds started in the middle ages, diamonds are naturally octagonal crystals, and until cutting was developed they were only used in their natural form. The first cut diamonds simply had their natural facets polished, then slowly the shape began to become more and more complex, with more facets added to increase the sparkle.
Garnets cut into faceted baguettes
Computer design and mathematical advances have been used to study how light travels through the stones, and have led to huge developments in cutting. The modern brilliant round cut was developed around 1900, and normally has 58 facets. Symmetry is hugely important to this process, as the pattern of facets are designed to bounce the light around to provide maximum reflection.
Faceted stones come in a variety of shapes, some standard and occasionally some which are more unusual. The different shapes and cuts are more or less complex, with a princess cut for example being a more complex way of cutting a square or rectangular stone.
Faceted and cabochon Labradorite, the faceted stone has a stronger peacock surface and appears darker. The cabochon stone looks lighter.
Basically it's all about sparkle, and that marvellous game of turning a ring under the light to watch the different surfaces reflect. With a transparent stone you are looking beyond the surface into the stone, but even with something more opaque stones facets will create more reflection on the surface.
When I first started making jewellery I didn't think I had much interest in faceted stones, I considered them really for use in very traditional pieces and not of much interest to me. Over time the sparkle has slowly pulled me in, and now I love thinking of new ways to incorporate faceted gems into my work.
Brilliant cut diamond Orbit ring