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GemSelect Reviews Precision and Native Cut Gemstones

GemSelect Reviews Precision Cut Gemstones and Native Cut Gemstones

Many precious gems, including rubies and sapphires, can be quite rare. In fact, several types of colored gemstones can be rarer than diamond. To add to their scarcity, the percentages of high quality gemstones that are extracted from said gem mines are but a small fraction of the actual deposits made available. Therefore, top grade sapphire, emerald and ruby are quite indeed, exceptionally rare specimens.

Because colored gemstones are so rare, gemstone cutters will attempt at all costs to preserve as much of the rough material when cutting valuable gems. The price per carat of these gems is so high that salvaging an extra 100 milligrams (.50 carat) of weight can make a significant and substantial difference regarding the business’s economics.

However, there are some tradeoffs to be encountered when trying to maximize the yield cut from rough, uncut stone. First off, generally the shape of any finished stone will usually reflect the shape of the rough material. This is the reason why you won't find many round-shaped rubies or sapphires, especially in larger premium sizes. The rough stones tend to yield mainly oval shape finished pieces, with some fancy cushions and pear shapes becoming available. A more serious tradeoff is occasional bad or poor cutting of gems, which can affect the beauty of any gemstone.

Native Cut’ is a term used often and refers to a range of cutting faults that can sometimes be the result of an overeager attempt to maximize the carat weight of a rough stone. The most common seen error is cutting a gemstone with too large off a face with a shallow pavilion, resulting in an undesired phenomenon known as ‘windowing’. A gem with windowing effects has an unfortunate characteristic where it will display an area of diminished color in the center of the gem, meaning some light rays pass directly through the stone rather than reflect back to the eye displaying brilliance.

With colored gemstones, cut is not nearly as important, like it is in the world of diamonds. The most critical aspects with colored stones are undoubtedly color and clarity, and the gems’ respective cuts should enhance and not detract from these key characteristics. In summary, a colored gemstone should be cut with proper proportions, the culet should be centered, and the stone should display minimal to no windowing or extinction (dark areas where light passes through and is not reflected back to the eye).

Some colored gemstones are now being cut with advanced technology; faceting machines that allow precise controls over the cutting of facet angles. These precision machines can yield extremely good results and require less skill from the cutter compared to traditional cutting methods. However, precision cutting will never be able to compensate for inferior materials. Fine gemstone material with an adequate grade cut will surely yield much higher results than precision cutting of gems with mediocre grade material.

From time to time, GemSelect will purchase gems that are of fine material but poorly cut. But we will only purchase such stones, if we think that they can be successfully re-cut to eliminate windowing effects and / or improve the fire and brilliance of the stone. The end results are usually excellent and better than expected, but re-cutting a stone in this manner will always incur some amount of weight loss (since the stone must be completely re-faceted). The price per carat of a re-cut gemstone will naturally be higher, but it is money well spent.

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