You can buy ceiling medallions at your big box stores or at a lighting store like I did. They aren't very expensive depending on how large and how much detail is on them. This is an old photo so that is why the stuff on the wall is different.
I usually work on my kitchen counter with a drop cloth down.
I dry brushed some Graphite here and there for more depth. I love how it turned out and I do think it looks like stone.
This is what it looks like today.
If it hadn't turned out like I wanted I would have just started over with more paint.
That's the beauty of paint!
This is the first medallion I painted in 2011 in the dining room. You can see how I painted it here.