The green marble doesn't bother me near as much as the almond framed mirror you selected.

I have thought about maybe painting it or getting something new. Any suggestions for colour of mirror?

Green and pink are usually a nice combo. Maybe your pink isn't the best match for the green (which looks black on my monitor, btw)?

Here are alternate suggestions

The green marble is actually a perfect complement to the fuchsia wall, but if you absolutely hate it, then you absolutely should change it—but I’m not sure paint is the right way to go. Speaking of paint: Would you consider painting the rest of the walls in this room fuchsia?

As for the color of the mirror, I don’t think it’s bad at all. However, the two lanterns and the candle holder aren’t adding anything positive to this mantel vignette.

I would not suggest painting marble, especially around a hot fireplace. You can either replace the surround of the fireplace with a marble that would complement the wall color, or keep the green and soften the pink of the walls. Also, the mirror could be a little larger if you are inclined to purchase another one, otherwise, painting the frame either, white, silver, gold or black--depending on the other furniture and fixtures in the room.