I am very interested of getting this 18karat Japan Gold Ball Stud Earrings from a Japan based seller. This is the only 18karat ball stud earrings that I found and at a good price. Most were 14karat. However, the back of the earrings is 18karat gold coated with silicon. I do not know if that would be a concern. I do not have other earrings with that type of back. It seems Japan made earrings always have that. Does it make the earrings look cheap? I am also afraid that the silicon would turn yellow after some time and I may not be able to clean. I do not understand also the purpose of silicon. Do you have these type of backs on any of your earrings?