They’re based off of the gems they are, not the race you supposedly forced on these alien creatures who have no race or gender.
Every crystal is known to have different physical and emotional properties to them and Steven Universe has mostly followed that. Thats how many people knew Peridot was going to become part of the Crystal Gems as soon as it was known she’s a Peridot, because peridot is literally known to have the property of redemption, renewal, and growth.