This is a beautiful gemstone. I never realized until I started posting my collection that I had so many blue to blue green medium dark gemstones. This one has to be one of the best. It is eye clean and with excellent crystal. This makes it quit flashy even with a medium dark tone level. Another factor that is important in making a gemstone bright, beside the cut and qualities of the rough, is the polish, I take my time using Alumina on a stationary tin lead lap to make the polishing of every individual facet count. I have never gone for a commercial polish and I never will, even when the poor tourmaline would like to be put out of its misery. This GEM, exceptional gemstone, weighs 4.34 carats and when it is under my yellowish light, it reminds me of synthetic emerald, that always seems to be a darker green with a bluish cast.