Cuttin' Up with Drew - A Beryl of Monkeys: Tips & Tricks for Faceting Emeralds

July 28, 2017

 

     Emeralds, the bright green variety of the mineral Beryl, are one of the rarest gemstones in the world. In the entire North American continent, North Carolina remains the only location where emeralds naturally occur. Although most emeralds found in Hiddenite are light in color, many dark green gems have been found here and cut into museum-quality faceted stones.

     A big misconception I have heard time and time again is “Emeralds are soft stones”. On the contrary, emeralds have a MOHS hardness similar to quartz (7-7.5), and takes an even better polish.  However achieving a beautiful, natural cut emerald without using oils or heat treatment is no easy task. Many factors are considered when evaluating which emeralds will cut and how we can do so. The biggest factor in terms of value is the color. Richer green equals higher price, but looks can be deceiving. The color is the result of trace amounts of chromium (Cr) in the chemical composition.

     Often times the green saturation zone in the emerald is restricted to the outer ring or the rind of the crystal (like the peel of a fruit). When light travels through this chromium-rich zone it scatters through the body of the crystal and can sometimes mislead gem cutters. The best way to capture the color is using an octagonal cut, dubbed the Emerald Cut, so that the outer crystal face containing the chromium is used as the Table- the flat top of the gem.

     Typically faceted stones are cut on the bottom first to achieve the critical angle. Emeralds are cut differently. The table of the emerald is cut and polished first to ensure that the color is captured in the upper-most portion of the gem. Natural emeralds always have inclusions which can scatter light and help the color but clarity is still more desirable. After getting the table polished, the rest of the cut is all based on getting rid of fractures and inclusions while still maintaining the maximum carat-weight with the correct proportions.

     To have your emeralds evaluated for cutting opportunities, bring them into our shop any time or call us at the Emerald Hollow Mine Lapidary or contact me via the email form on this page.

 

 

 

 

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