S925 is pure silver (international standard, that is, 92.5% silver and 25% other metals).

20 means that the number of rings is 20.

LZ, did you buy a square circle or a circle? Generally, the square circle will be bigger and heavier, and the circle will be smaller and lighter. You can weigh the ring. But I guess you were cheated. Even if you weigh 30 grams per gram, the unit price is 20 yuan/gram (already on the high side), which is not as good as 600 yuan.