Someone who's tiny and a bit fragile can be described as elfin. Your grandmother might be especially proud of her little elfin feet.
Small people and children are often described as having elfin faces, particularly if there's a mischievous spark in their eyes. If your friend's ears are unusually petite — and rather adorable — you can describe them as elfin. The word clearly comes from elf, and it's sometimes used to mean "relating to elves," though it more commonly means "tiny like an elf." Edmund Spenser first used the word elfin in his 1590 epic poem, "The Faerie Queene."