Fireplaces, Heating Stoves, Flues and Chimneys - How to hang a picture on a rock over brick fireplace?

I know this is probably a silly question but do I need a special type of "nail gun" or something to shoot a nail into my fireplace? The fireplace has "fake" manmade concrete rocks over the brick-yes, ugly, think Flintstones. I have a large painting that I want to help hide the ugly fireplace but can not hammer anything in it-help! I've tried twistin wire around the rocks and other assorted tricks but nothing works.

What exact tool do I need to buy to do this? About how much is the tool? Rent it? If I make a mistake "shooting" the nail and the concrete rock chips or breaks, can I repair it easily? Thanks in advance for your help!

The fireplace has a gas insert so the painting won't get ruined from real wood burning(I hope!)

I would just drill a hole and insert a Tapcon screw into the rock joint.

Thanks so much Larry! I never even thought about drilling a hole-ugh. I have a Skill Drill with the little box of 15 different bits. Are they the appropriate type drill bits or do I need to buy a special one. I am getting ready to go to the orange box store now so I will look for those special tapcon screws. The picture is about 4" wide and light weight so I think I can just use one.