J is jewelry, jewelry decorations

Refers to jewelry and ornaments made of jewelry and precious metals, covering semi-finished products with certain geometric shapes, such as ring faces. Including non-inlaid jewelry and inlaid jewelry.

Ct is the symbol of carat, carat 1 carat = 0.2g (200mg).

This is a sign provided by jewelry merchants themselves according to the regulations on jewelry identification. Specifically, there should also be an identification certificate with pictures issued by the inspection agency stipulated by the state.