Hey,
Welcome. It is Finnish, the single crown tells that, see
Finland Date MarksIf it were Swedish, it would have a triple crown mark, see
Sweden Date MarksI'm pretty sure that "Warman's Jewelry" by Christie Romero, shows your KK maker's mark as the firm of Kaunis Koru. (can't seem to find my copy in the mess)
Hope this helps.
Fin