If you’ve ever seen raw gemstones, you might have been surprised how dull they looked. Where’s the glint? Well, for most stones the glint is trapped inside until an expert gem cutter sets to work. The task is to cut the stone to set off its color and minimize inclusions while preserving as much of the stone’s weight as possible. An inclusion is a fragment of another substance or a cavity that detracts from the gem’s value.   The best way to cut stones varies radically from one to another. Some, such as turquoise, require little more than a good polish. Others have rigid crystalline structures which shatter if cut the wrong way.  Some stones, such as diamonds, have structures allowing for more complex cuts. When a stone allows different approaches, the gem cutter will decide which cut maximizes shine or fits a client’s preferred setting.   When picking jewelry, keep in mind that you want a symmetrical gem that uniformly reflects light across its surface. The polish should be smooth and scratch-free.    Cabochon Cut   This is the simplest and most ancient cut. The stone is round on top, flat on the bottom, with no facets. You’ll see this cut in semi-precious stones like tiger’s eye and moonstones. It’s also used for star gems, such as star sapphires and star rubies. In the last few years, the cabochon has also become a trendy cut for emeralds.   Round Brilliant Cut This most popular shape for diamonds was created in 1919 by Marcel Tolkowsky. Seen from the side, it looks like a cone: round on top and pointy on bottom. Brilliant cut allows the maximum amount of light to enter the stone, explaining the squint-inducing glint of the best diamonds. Sadly, cutting a diamond into this shape results in losing about half your original stone.     Oval Cut   A popular shape for high quality colored gemstones, the oval cut has a length to width ratio of about 2:1. A standard oval cut gem has 69 facets. Viewed from the top, it looks elliptical. In the hands of a talented gem cutter, the oval can sparkle nearly as much as the round brilliant cut.     Emerald Cut Emerald cuts are – not surprisingly – a top cut for emeralds. At first glance, emerald cut stones look rectangular. But they’re actually octagonal. Equidistant steps around the stone’s edges rise up to the central pavilion. This cut was originally designed to reduce pressure on emeralds and prevent chipping. But now you can find many stones in emerald cut.     Princess Cut   Tiffany & Co. refers to princess cut as “elegant and dramatic.” From the top, it looks square. From the side, a princess cut gem resembles an inverted pyramid. After the round brilliant, this is the number two cut for diamonds. Princess cuts are popular with diamond cutters, as they can retain more of the raw gem than when using a brilliant cut. This cut first entered the gem scene in the 1960s.