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Peridot Jewelry
 COMMON GEMSTONE SHAPES

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EMERALD

HEART

MARQUISE

OVAL

PEAR

PRINCESS

ROUND

TRILLION

 

GEMSTONE SHAPES AND FACETING

     In nature, the shape of a gemstone is determined by its natural crystal structure and the conditions under which the crystal developed.  To enhance the natural beauty of the crystal and to provide a safe shape for mounting, gem cutters form natural gemstones into precise shapes. These shapes typically include a number of flat, symmetrical planes, called facets, which reflect light to add sparkle and brilliance to the finished stone.

     Gemstone cutting is based in science.  Each gem material has a known refractive index which allows a gem cutter to determine how light rays will bend as they pass through the stone.  Using this information a gemstone can then be precisely shaped to best enhance its natural beauty.

     If a well shaped multi-faceted stone is viewed from above it will appear very bright across the entire surface. This brightness results from light rays being reflected directly from the top surface, as well being reflected within the gemstone and back to your eye. You cannot see through a well cut gemstone, even though the natural material is translucent, since almost all of the light is being reflected back to the viewer.  [Obviously this is not the case with stones which are intentionally shaped with larger facets, such as a traditional emerald cut.] 

     If a gemstone is not as well shaped it will be possible to look down on the top surface and see through to the point at the bottom of the stone.  This transparent effect is called a "window."  Windows detract from the brilliance and color of a stone, since light be allowed to pass directly through the materials without reflecting back to the viewers eye.

     Not all gemstones are faceted.  For example, opals are suited to a smooth, rounded surface, and are often found with pleasing shapes which naturally highlight their internal flashes and sparkles.  Other gems are formed into smooth, rounded shapes called cabochons.  Some "cabo's" are are also referred to as "star" gems due to the distinctive light pattern which appears as a result of inclusions in the stone.

 

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