These are great earrings, according to the description they are 1/4” in diameter, which is approximately 6 mm. The ones I received are about 4mm. They would be perfect for a 2nd or 3rd piercing, I unfortunately only have one piercing in my ears. They are beautiful, purchased the abalone. Wish they were a little larger, tried to contact Boma, but for some reason my email keeps getting rejected. Meaning they are not going through to Boma from my end, either way they are quite beautiful earrings, v...