Is having to wear pure gold or silver earrings after a piercing a myth?
No it’s not a myth and even part of the statement is incorrect. You cannot even wear silver either and only a very high karat gold (I recommend 22k or higher, Nobium, surgical stainless and some plastics).
Pure silver oxidizes rapidly, pure silver even faster. Imagine what it would do inside the moist environment of your skin. Bad, bad choice. Any metal that either naturally oxidizes in air is not good enough for a new piercing. Think about grandma’s tarnished tea set. Imagine this inside your skin.
14k gold is not good enough either for most people. Some can tolerate 18k. I usually custom make the piercing jewelry for my clients and always at least 22k although I recommend nobium for the first 10 weeks then come back for gold. Don’t use silver for about a year. (For body piercings that is, ear lobes seem to heal quicker; everyone is different)
It is no myth. Surgical steel or gold, as pure as you can afford. Some people won’t have a reaction with dirty tin, or an old safety pin. Some will. You want to minimize the possibility of infection, irritation, or inflammation; none of those things will feel good or look nice.
Oltin, and if that’s out of your price range, surgical steel, which anyplace that does piercings should sell, is the way to go.