This is closely linked to their unique light-refracting properties and the material loss involved in their creation. First, light refraction gives diamonds their brilliant sparkle; to ensure light reflects evenly from the top, cutters meticulously design symmetrical facets aligned with the culet and the center of the table. Second, the process of cutting a round brilliant diamond results in a material loss of up to 47%, leaving only 53% of the original rough stone.
In contrast, fancy-shaped diamonds incur less material loss, retaining 55% to 60% of the carat weight. This rarity contributes to the high value of round brilliant diamonds.
Fancy-shaped diamonds offer a relatively higher yield due to their diverse forms. For instance, heart and pear shapes allow for efficient use of the rough stone, achieving a yield of up to 50%, whereas using the same rough stone to create a round brilliant diamond would yield only about 30%. Consequently, fancy-shaped diamonds are more material-efficient, and their price is typically around 80% of that of a standard round brilliant diamond.
