This Sterling Silver Ring with Peridot and 9kt Yellow gold trim is made using a technique called Reticulation. It requires great skill to cause the outer surface of the silver to "melt and bubble" without melting the entire Ring.
The entire Ring is then Oxidised to darken the surface and highlight the irregularities.
In this Ring the Peridot is also set in a 9kt Yellow Gold setting.
See:
www.philipthornton.co.nz
www.24sevenjewellers.com