I happened to spot a 2 carat pear shape diamond on solitaire setting, and stone looks so big compare to 2c round. I wonder how all the weight of a 2c get spread around for pear to appear so big.
Many fancy shapes look larger than rounds because they are a lot thinner toward the pointed ends. (Pear & Marquise). An oval even is a little thinner toward the rounder ends, too.