For TVs that are under 23.6″ tall the mount may be taller then the TV in the top position.
To mount to your fireplace you will have to first make sure that your stone/brick is sturdy enough to hold the TV mount. Then purchase special brick/concrete anchors such as the ones in this link http://www.mcmaster.com/#brick-anchors/=llbka0, Use one of the 1/2″ Dia.—Thread: 3/8″-16; Head Width: 9/16″; Washer OD: 1″ (Drill Size 1/2″). You will have to figure out the correct length for yourself. Or if you can drill all of the way through use something like this, http://www.mcmaster.com/#97802a317/=vslqia. I would suggest using at least 3 of these in the top row; these anchors are the ones that do most of the work. To drill into the stone/brick you will probably need a special drill called a hammer drill, which you can rent from the hardware store along with the correct size bit. Using the hammer drill is just as easy as using a regular drill. After you have the hammer drill and anchors you can follow the exact same directions that are in the manual. We are not professional masons so I would suggest getting a professional opinion if you have any other questions.