Emerald cut :
This square or rectangle cut was developed to address natural weakness of emeralds due to the high quantity of inclusions it contains. It is widely used to cut other gemstones than diamond.
Carat :
The carat (ct) is a unit of mass equal to 2 g. Carat is used for measuring the weight of gemstones.
Emerald :
Emerald is a gemstone, a variety of beryl colored in green by trace amounts of chromium, vanadium and sometimes iron. Emerald frequently contain many inclusions, with a result of poor resistance to breakage making their cutting very difficult.