Crating a Gem with native code

Hi all,
I need to embed the FireFox engine in a pet project of mine I’m working on. I have a couple of questions.

  1. Does such a Gem already exist? There’s no point in re-inventing the wheel if it does.
  2. If not, where can I find a good example of writing a gem with embedded code? I’ve looked online, and all the tutorials I’ve found use only ruby code. I was thinking that the MySQL gem with native drivers might be a good example, but I’d like to look at a couple more before I proceed.