Is there anyway to partially de-friend a friend?

I have been in this situation, I swear. The best thing you can probably do is to find exuses that are legitimate sounding not to hang out all the time, and over a period of months just gradually decrease it in tiny amounts. Otherwise, next time she says something blunt or jerky respond back! Say "That's a little Harsh! What do you mean?!". Or try Saying "I can't believe you just said that! Be Nice!" Let her know her behavior is disturbing to you-if she can deliberately be "jerky" she should certainly be able to handle knowing you don't think she's perfect. Consider making yourself a little more "boring" at work, and hopefully, she'll slowly move on. Good luck.