Your granite can probably be easily buffed back by a professional. The problem for a DIY'er is the cost of the machine and the cost of the polish and/or diamond pads. Then there's knowing just what to do to.

Buildinva

I managed to take the finish off my bathroom countertop and it feels the same (who knew that rust remover could be so harsh...duh!). It is a nice countertop (silestone) and that patch is now covered with a conch shell...lol. Not the best solution but it works for now! Easier to do in a bathroom than in a kitchen though! Hope you manage to get it fixed :)

That is scary that baking soda would do that. I thought baking soda was a gentle cleaner.

True, I never would have thought that baking soda could harm anything!

Are you sure you've made scratches IN the granite, or might you have a residue ON TOP after using the baking soda? We have a low grade granite in a powder room. A few months after it was installed I noticed that the sheen had dulled in spots near the faucet handles. I tried a few different cleaners but nothing brought back the shine. Then I saw someone post (here I think) that it's impossible to remove the finish from granite, so I took a closer look. It was just hard water deposits. I grabbed a razor blade and spent two minutes scraping and -voila!- good as new.

I too use a razor blade to get off mineral deposits.