Round Shape Gems
When it comes to gemstone shapes, round gems are the most popular and versatile. Unlike oval gems, round gemstones are not cut to maximize carat weight, so more skill is often required by the cutter to bring out the color and brilliance in a gem. Many people confuse shape with gemstone cut, which isn't all that surprising. Looking at our selection of round-shaped gemstones, you'll notice a number of different round-cut stones; some are cut en cabochon, with no facets at all, while others are faceted in the traditional way, either with step-cut faceting or with more angular 'brilliant-cut' faceting. Other round gems may be given an unusual or mixed gem cut, such as concave-style cut, checkerboard cuts, or Portuguese-style cuts. Round rose-cut gems and round buff-top gems can also be found. Thus, it is easy to see why shape and cut are often confused, because there is one shape (round) with multiple cutting styles. Although many describe their gemstones using terms like 'round-cut', it isn't always the best description since there are many cutting styles; technically gems should be described as 'round Portuguese-cut', 'round step-cut', or 'round cabochon' for example.
The meaning of shape should be fairly obvious, which is the face-up outline of the stone, whether it is round, oval, square, rectangular, pear, marquise or trillion. Round gemstones should be symmetrical with a perfectly circular outline. However, in practice, a good percentage of gemstones are native-cut without the use of precision lasers and other advanced lapidary tools, so many round gems are not actually perfect circles and are rather better described as being near-round. This is why you may find that many still use three measurements for round gems. Most gemstone dealers will use only one diameter measurement and the depth (in millimeters), but to be more accurate, some dealers may advertise their items using the two diameter measurements, with one measurement at its minimum and another at its maximum, followed by the depth in millimeters. This type of measuring is more often used for diamonds rather than colored stones.