Etching & lamination work on casting jewellery

we are in constant lookout for different surface finish of
casting jewellery . Recently I came across some very good
etching work done on plain pendans. I am very much intrested in
doing some kind of etching job done on the jewellery which we
manufacture if some one can send me some on the
technique of doing etching work on gold jewellery & the
machinery required would be very useful to me . also any kind of
lamination work that can be done in gold jewellery Thanking you