Gemstone Shapes Explained
by Shawna Edwards
April 28, 2010 | Updated July 27, 2015
Perhaps no accessory adds more sparkle and enchantment to your wardrobe than gemstone jewelry. The vibrant color is a big draw, but the cut of the stone also greatly affects the overall design and feel of a piece; round stones convey a sense of tradition and romance while straight edges seem more modern and sophisticated. Jewelers rely on a standardized set of gemstone shapes to cut stones into dazzling jewels.
Popular Gemstone Shapes:
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- Round Brilliant
The most popular shape for gemstones, the round brilliant-cut also offers the most sparkle. The classic round brilliant has 58 facets, mathematically arranged to reflect the maximum amount of light out the top of the stone. When cut inaccurately, the stone allows light to leak out the lower portion instead, and it appears dull.
This cut is an elliptical version of the round brilliant, usually with 56 facets. It was invented in the early 1960s and has become a popular shape since. The oval-cut stone may display the "bow-tie" effect that allows light to pass directly through the stone without being reflected back.
The 56-faceted marquise-cut is oval-shaped with points at both ends. Legend has it that Louis XIV, the Sun King of France, requested a diamond polished into the shape of the Marquise of Pompadour's mouth. This beautiful cut, named for Lady Pompadour, was the result. Some marquise-cut stones display the bow-tie effect visible to the unaided eye.
Shaped like the oval-cut at one end and the marquise at the other, this teardrop shape appears frequently in pendants and earrings. Like both the oval and the marquise, this gemstone cut is subject to the bow-tie effect.
The heart brilliant resembles the pear cut, except for the cleft in the rounded end. In fact, a diamond cutter may choose the heart shape because of an inclusion located in that part of the stone. Like the oval, marquise, and pear shapes, this cut could display the bow-tie effect.
Another variation of the brilliant-cut, the princess is a square-shaped stone, usually a diamond, with edges that meet at 90 degree angles. You'll see them often in channel-set and invisible-set jewelry where the gems are set edge-to-edge for nearly seamless brilliance. Princess-cut diamonds are an especially popular choice for eternity rings.
With broad, flat facets that resemble steps, the emerald-cut is rectangular with beveled corners. This cut makes any inclusions or color flaws in the gem more noticeable, so jewelers often choose higher quality stones when using it. Unlike other fancy-cut shapes, the emerald-cut does not display the bow-tie effect.
Another rectangular-cut, the baguette has fewer facets than the brilliant-cut, with a flat top and four flat, beveled edges. Like princess-cut stones, baguettes are often set edge-to-edge for a seamless look. Some baguettes have a tapered cut so they'll fit smoothly around curves.
Ideal-Cut Round Brilliant Gemstones:
Cut to specific proportions, an "ideal-cut" round brilliant diamond refracts and reflects almost all light that enters it, creating maximum sparkle. This cut comes at a premium, for more weight from the rough gemstone is lost as waste, making the ideal-cut gem costlier than other stones of similar carat weight, clarity, and color. Most jewelry manufacturers prefer to retain more weight in the finished stone and use other cutting proportions that balance brilliance with finished carat weight.