I have the multi color pinkish/gray marble on the front of the fireplace?
hunker.com has an article about painting over marble using chalk paint rather than other types of paint. I've never done this so I don't know how well it will work or how long it will stand up to normal wear. Read over the article to start your research. Wishing you the best.
Scuff the surface with 220 grit sandpaper to remove the shine. Clean well. Prime with Kilz primer then paint.
Use the epoxy paint kits made to go over ceramic tile for best results.
You could ether just paint it with paint or add another color to it to change the look