Cris,
Even when I make a new "old style" piece of jewelry it is never shiny. I will polish the piece and then lightly oxidize it then I will finish it off by rubbing the highlights with 0000 steel wool. You just slightly hit the high spots. In doing this you retain a good portion of the patina and the silver is not super shiny.

I have added an image of a bracelet done with this technique. I think if you do this to your necklace you will be very pleased with the results.

You can get 0000 steel wool at most hardware stores.

All my best ....... Danny