I’m going to try to give people an overview of the process without getting into the fine technical aspects of gem cutting. If I get requests from people who have technical questions I will do my best to answer them and perhaps I will expand more as time goes on. Each type of gemstone has different properties that require a specific way of handling. They might require lukewarm water when cutting and polishing, or they will crack. Too much heat from friction combined with cold water when polishing can cause cracking. Different types of gemstones need different polishing methods, and so on. Sapphire and ruby need to be polished with diamond paste or spray.
For now I would like to discuss the two main philosophies connected with the faceting of gems. The radiant cut and what I call the heavy bottom cut. The radiant cuts are computer aided designs that started to be published in the 1980’s. The diagrams have very accurate directions for the cutter. I have hundreds of diagrams to select from that will guide me for any size or shape of rough gemstone. I have an example to the right side of this page. The name of the cut is Eagle Eye. It was published by a man named Fred Van Zant. Fred was a prolific designer of
gem designs and a brilliant man. This type of cutting creates a stone with lots of sparkle from inside the stone, but also squanders a lot of good rough. On average a 25 to 30 % yield. That means we loose 75% of the stone! It may also lighten the depth of color. Something you don’t want on a good emerald; for example. Yes, it’s great on certain types of gems that are found in large pieces. However, it doesn’t pay to squander rough on scarce gems of high quality. This is why hobbyists vs. cutting houses can conflict on methods. The more or less rounded bottom (although still faceted) on commercially cut stones keeps more weight on the stone and produces a pool of color saturation that is desirable on rare stones.
From the mines to the cutting houses is also a fascinating subject. Can you imagine buying a 55 gallon drum filled with sapphires? What would you do with all of those gems? You better be able to cut them. AND you better have a market to sell them once they are cut. Everything in the barrel is called mine run. You take those stones to your cutting house and the first thing you do is sort them by quality. This is known as high grading. Faceting material. Cabochon material. And lastly tumbling material. And then we can break this down to other categories such as beads and melee (the little stones that surround the major stone in a setting). Well guys; you see that it takes a factory to do this. You invested say 1.5 million and now you need to feed your family!
So ok, I had a teacher that was a proponent of the radiant cut. Nice work, but not that practical in the market place. I want you to try to understand why certain collectible stones are cut the way you see them and not let yourself be swayed by the arguments of certain purists.