A heart shaped diamond has a cleft at the top of the stone and typically flaunts great brilliance. For obvious reasons, heart shaped diamonds are considered the most romantic of all the diamond shapes. When finding the right heart diamond for an engagement ring, symmetry must not be overlooked – the two halves of the heart should be identical. As a general rule, heart shaped diamonds smaller than .50 carats are not a good selection, as they will appear smaller after being set in prongs. Three prong and bezel settings are the best match for heart diamonds.