CN signifies that the jewellery is produced in China, Whilst the letter D stands for solitaire diamond, indicating that just one diamond is used in the ring. For that reason, if a ring has N 925 Cn stamped on it, This is a normal sterling silver ring built in China. https://lanebobmx.blogoscience.com/43266886/the-smart-trick-of-jp88-that-nobody-is-discussing