I changed my mind. Here are your two stones. Your selection depends on the furnishings in your room or the direction you want to take the room. One is warm and the other is a cold appearance. I would select the warm colored quartz.

Artic Golden

Glacier White.

Now that I see great photos of the stone, I also voted for the Artic Golden, which helps to keep the room from looking too cold and sterile.

IMO stacked stone is already a dated look and I like a much simpler facing on a fireplace . Look at large format 12 x 24 tile instead a nicer look and so much easier to dust . Maybe post some pics of the rest of the space and we can give better advice.