Quite possibly the most popular size of diamond stud earrings is 1 carat TCW. This size is big enough for being visible and fits a popular spending budget people have for diamond earrings. My favourite pair of 1 cttw studs are these stunners in a white gold martini location from https://flenzy.store/timeless-heart-cubic-zirconia-stud-earrings-for-women/