Jeni, different patinas can be produced on sterling silver by using liver of sulfur. It isn't expensive, it stinks like rotten eggs though so it's best done outside. Put some boiling water in a cup and add a small lump of the liver of sulfur, about the size of a pea, stir it up to dissolve it then dip the piece you want to patina in and out of the cup until you like the color. The more often the piece is dipped the darker it gets but in between no patina and flat black there can be a number of different interesting colors. The whole process is pretty variable, there's no way to come up with one particular color over another, say, or even to duplicate the same color twice. It's fun though, if you can stand the smell, LOL. Then you can laquer the piece to help preserve the patina but what you wouldn't want to do is subject it to a lot of wear, say in a bracelet that would be worn while putting a coat on and off repeatedly as it could still wear off that way.
Kay, a fired on patina could wear into something else but not really come off, but that would take a good amount of time, months to a year or more maybe depending on wear factors like with the liver of sulfur. These are just beautiful with that red color!
Pam
It is only with the heart that one can see rightly, what is essential is invisible to the eye.
Antoine de Saint-Exupery