I had an ugly fireplace and I'm not wealthy, so my options were limited. My 'how to paint a fireplace' search resulted in a lot of pictures of painted fireplaces, but they were all a solid color and that just wasn't what I was looking for.
I'm very good at creative solutions and I'm very brave. I figured if it didn't work out, I could always repaint the thing a solid color (boring).
I wanted the fireplace to look like slate. I studied pictures of real slate on the net and decided that I could paint it. I went to Home Depot and bought three colors of Behr paint (slate blue, grey, brown) and Faux Finishing glaze.
When I got going, I decided three colors weren't going to cut it, so I dug around in the garage and found a green and a gold. The gold was some Oops paint we picked up for $5 several years ago. It turned out to have some metallic to it that really worked out well. The green was way too light, so I mixed in some artists acrylic black. (Yes, you can do that to make whatever colors you want. So cool!)
I started painting random bricks with each color. I was sending pictures as I finished each one to my husband, Wayne. Anyone else seeing this would have had a heart attack, but he's used to me. The people in his office were rather shocked, however.
The dark blue slate was way too dark compared to the rest of the bricks. I mixed up a wash of green and brushed it over the dark blue to lighten it up.