Some jewelry, In particular vintage or handcrafted items, may well not bear any visible markings. On the other hand, it's highly recommended to refer to with an experienced jeweler or appraiser to evaluate the piece’s value and guarantee its high-quality. There is no difference among the markings S925 and 925; https://landencrdoa.ampedpages.com/jp88-things-to-know-before-you-buy-63972528