Emeralds, as all gemstones, are cut into shapes for one simple reason, to highlight the beauty of the gemstone. After Emeralds are cut they are used mainly in jewelry applications, to be mounted in rings, earrings, bracelets, necklaces and so on.
Cutting Emeralds consists of three steps: First remove all impurities, then cut the gemstone faces and finally polish those faces.
The first step is done by cutting through the side of the gemstone considered to be less useful, the gem cutter pushes the emerald towards a spinning disk that removes all useless portions of the gem. After all impurities (or most of them) are gone, faces are cut into any shape desired or considered to be the best suited for that particular emerald. Finally, after the shape is well defined, all faces are polished to obtain the most reflectance possible out of the gemstone.
As emeralds are highly included, every step in the cutting process has to be performed very carefully, otherwise the gemstone might break. The Emerald cutter has to be someone experienced as he might guide you in the making of tough decisions like choosing the shape of the cut, and whether to keep an emerald as one single piece or cutting it into two different gemstones to get the best quality out of it. All of this decisions are based on the experience of cutting hundreds of emeralds.
Cutting Emeralds is relatively simple but has to be performed by experienced cutters to get the best possible result.