Emerald cut diamonds are a diamond that has been cut to a square or rectangular step cut with diagonally cut corners. Usually have 2 to 4 rows of parallel facets to the center of the stone. A very famous style of cut used for Emeralds hence the name.
The large flat face (table) when viewed from the top is that makes this cut unique. This flat face highlights the clarity of the diamond. So, only high quality diamonds are cut to this shape. The lack of impurities and inclusion in the stone will increase the price.
So emerald cut diamonds are usually more expensive than other cuts with the same caret weight. The classic shape of emerald cut diamonds has a length to width ratio of 1.30 to 1.40. The studies done back in the mid 1970s showed that the majority of successful business also had logos with the same length to width ratio. Other length to width ratios is available.
If they are pleasing to the eye is determined only by individual tastes. 1.75, 1.50 and 1.25 are very common, if you prefer a more square shape then take a look at the Asscher cut. It also has a flat face to highlight the clarity of emerald cut diamonds but has a length to width ratio of about 1.0 to 1.05. Be sure to review the clarity plot on the diamond certificate when you buy an emerald cut stone of SI clarity grade or lower.
A diamond is said to be Slightly Included (S.I.1 to S.I.2) when it presents defects that are easy to locate under 10x magnification. One of the most famous emeralds cut diamonds in the world is the Darya-I-Nur diamond. It's also believed to be the largest pink diamond in the world.
The stone is estimated to weigh somewhere between 175 and 195 carats. It is a light pink color. Its exact weight is not known because it is been mounted in its brooch setting for over 130 years. In the Iranian Crown Jewels, this stone is one of the most celebrated diamonds. It is also one of the oldest stones known to man.