This is personal preference, IMHO. Whether or not you want shiny is up to you. I'd go with something in the middle, like satin.

Yes, the matte or shininess is definitely a personal preference on a fireplace. I've used a satin paint before when redoing a fireplace, and have also used a brick primer, as well. There are many great tutorials available online.

Would you like color suggestions for the blue/gray? If so, what are your wall colors.

Thank you, MamaGray and Diana, for your input! I really really could use some help with color suggestion! The walls are soft white with (I think) green undertone. I wish I knew the name of that paint. And THANK YOU for reminding me that I'd need brick primer! The stone is faux stone, I wish I could add pictures, but for some reason the system gives me an error, when I try to upload them here.

Hi,
Glad to be of help! Here are three gray/blue colors to sample for your fireplace. Any of these could look great with a nearby wall that had green undertones.

Benjamin Moore Normandy 2129-40
http://www.myperfectcolor.com/en/color/102806_Benjamin-Moore-2129-40-Normandy-Blue

Benjamin Moore Britannia Blue 1623
http://www.myperfectcolor.com/en/color/5064_Benjamin-Moore-1623-Britannia-Blue

Benjamin Moore Deep Secret CSP-625
http://www.myperfectcolor.com/en/color/378911_Benjamin-Moore-CSP-625-deep-secret

Hope these are helpful in getting you started.

Diana

Does paint work on metal and can colors still be custom made?