Looks nice! Not sure why you want to go from stone to stone. I'm not sure the change from stone to stone will be that noticeable for the cost involved. I'd first clean the soot etc from the stone you have & change the fireplace screen & maybe the utensils, those easy fixes might be enough to change the look. If not, here are many photos, of types of stone used for fireplaces. https://www.houzz.com/photos/stone-fireplace-phbr0lbl-bl~l_142600