Is it it possible to mortar over top a brick fireplace using real stone and have it be safe and useable?

Interior or exterior? Thin stone or a full stone veneer? Is the brick attached to a stud or concrete wall or is it a brick cavity wall? I suppose it is possible by attaching metal lath to the brick but the right way to do it would be to remove the brick. A lot of factors to consider.

It is a 1915 old house I am asuming the whole thing is brick it is a wood fireplace trying to find out if I can use artificial or if I have to use real should I use cement board because it is a brick if that is necessary or not. Any help would be appriaciated. I am trying to do the exterior of the fireplace only the interior will remain brick.

Do you mean the brick on the outside of the house or the exterior brickoutside the firebox but in the room? I have used this faux stone with great success. Eldorado Stone (http://www.eldoradostone.com/flashsite/main.html) It can be applied over brick , concrete or lumberusing masons mortar. Brick probably would not need wire lath but concrete and lumber need the lath to make good adhesion.

Thank you I was talking about outside the firebox I can use faux and wire mesh that is great

Won't need the wire mesh on brick but you can if you are worried about not getting it just right. Mesh on brick is like wearing a raincoat in a submarine, just insurance.