The best ratio for a round diamond is 1.00. Diamonds with a ratio of 1.01-1.03 will also suffice.   

Round-cut diamonds have 57-58 facets.

Round engagement rings represent tradition and timelessness. Those who wear one don't bend to trends and have confidence in their own tastes. 

Round-cut diamonds are the most popular choice for engagement rings, but they're not your only option. There are a variety of other diamond shapes to choose from - learn about them here.

Round-cut diamonds are the most expensive shape, so expect to pay a little extra for a round-cut engagement ring. However, the price of a round engagement ring varies on many factors, such as the size of the stone, the quality of the stone, and its origin - lab-grown diamonds will cost less than earth-grown diamonds.