Lapis lazuli and ruby in zoisite sterling silver open ring

This is a one of a kind sterling silver open ring. The stones are 2.5 cm and 2 cm long, the inner diameter of the ring is about 17.5 mm.

So the size would be US 7. 7 1/4, 71/2; N 1/2, O, O 1/2;

Silver, zoisite, lapis lazuli