This is a beautiful gemstone. Its acid yellow green color seems to burn a hold threw the little plastic box I store it in. Its medium toned splendor is augmented by having copper as a chromophore in its chemistry. I did not buy the rough for this gemstone as cuprian, so I was surprise to find copper’s signature absorption peaks in the gemstone with my spectrometer. I personally think that copper is helping this yellow green GEM (exceptional gemstone) have that “neon” look that is associated with cuprian tourmaline. I really have no way of knowing. This gemstone weighs 3.17 carats and has a color that should get more respect in the Trade.