Double shame on anyone who asks this about an engagement ring. Way to not-so-subtlely burst her bubble.
Can I extend this gripe to people asking how much your piece cost? I don't care if it's someone really close, but anyone else and it bugs me. My boyfriend's sister is really bad for this. I purchased my first diamond RHR last week and she baldly asked how much it cost. I've only known her a few months so it made me feel uncomfortable... especially when I replied with "Oh, enough!" she asked me
again. "
So, how much did it cost?"

Take a hint please! It's rude. Every cent was my own too, none of his, so she really had no excuse to sticky beak.
Then later in front of everyone she was going on to my boyfriend about how he's reeeeally going to be sent broke for my engagement ring. Only the females picked up on the b*tchy tone. Sigh.