Emerald belongs to the beryl group. Its closest "relatives" are aquamarine and heliodor.
This stone, together with sapphire, ruby and diamond, belongs to the stones of the first category. However, unlike them, the emerald is quite fragile. With a hardness index of 7.5-8.0 on the Mohs scale, emerald, often characterized by an abundance of inclusions, is extremely prone to chipping under even moderate mechanical stress. For this reason, emeralds are often cut in the form of a cabochon or a special emerald cut. This minimizes the chipping of raw materials during processing.