I have a book from year 1948 written in Swedish. I don't know from which year the modern marking of gold is from, but in this book they mention A, A2, A3, A4, A5, A6 and A7 and each letter means an interval of certain years.
According to that there should be name of the goldsmith, place, karat and some control.
If I have a tiny thing with mark A6 then I know that the thing should be from some certain interval.
Who knows if this is correct? Is there somebody who can tell more about this matter, please, do it then.