6mm sapphire gemstones are set in a 4 prong sterling silver setting for a beautiful blue pair of earrings, perfect for everyday wear or more formal occasions. Not only that, but as sapphire is the September birthstone, these earrings would make a very welcome September birthday gift. Weighing just less than 1 gram as a pair and stamped with a 925 metal mark, they have butterfly backs to keep them in place.