May Birthstone – Emerald

Determining Emerald Quality

It is often difficult to determine the quality of chunk emerald in the rough.  Sometimes a gemstone cutter will have to cut away more than 50% of the rough stone to determine what the quality of the final gemstone is, which may end up weighing barely one carat and hopefully be one of fine quality.

But what determines fine quality?  We go back to the “C’s” — color, clarity, cut and carat.  With emerald it’s all about color.  The finest emeralds will exhibit a rich, slightly bluish green color with good saturation throughout the gemstone and without inclusions that are visible to the naked eye.  99.99% of all emeralds are “oiled.”  This is done to mask the natural inclusions that are inherent in emeralds.  Many emeralds are cut in the “emerald” style cut which we associate with the emerald but also show the color of the gemstone to its advantage. And lastly is carat, naturally we’d like a larger emerald if we were to choose but the larger and more perfect the emerald, the rarer it is and the greater the price per carat.

A few of the more notable emeralds are the Chalk emerald ring containing a 37.82 carat emerald, the Mogul emerald weighs in at 217.80 carats, and the Duke of Devonshire emerald, one of the world’s largest uncut emeralds, weighs in at and an amazing 1,383.93 carats.