Although ear piercing is dated to Biblical times, in America vintage earrings from 1900 to 1960 are typically clip-ons. When shopping for antique earrings consider this - It is more rare to find studded earrings from the turn of century through the sixties. Traditional ear piercing regained commercial popularity in the mid 1970s.
Pearls were also often used in combination with diamonds and gold. Before diamonds were popular, pearls were one of the most prized pieces of jewelry. This is why you still see pearls in contemporary earrings.