Cut has for many years been much overlooked and has in recent years come to the fore. Cut refers not to the shape (as in round, square, etc) but to the cut of the stone. How well or poorly it is cut. This will have a large impact on the beauty of the finished stone. How well or proportionately the stone is cut will effect how much light is reflected back when you look into it. If the stone is cut poorly, light will escape the stone and this will be lost as will the ‘fire’.
If I could make the recommendation to anyone who has the budget for it, a Hearts and Arrows stone or “ideal cut”, no matter the brand, will be worth it. They truly are a most beautiful diamond.