Please describe what you are trying to do? They make metal fire pits. Do you want a brick one? Do you want a circle of rocks for a bonfire with a hood over the top? Do you have any concerns about smoke, soot, creosote, carbon monoxide, and other combustion byproducts circulating in your house and on all surfaces. Ventilation is a major problem if not done right.
Be careful that your indoor firepit doesn't turn into an outdoor firepit when the house burns down. Talk to your building/inspection dept. and see if your homeowner's insurance has any requirements so you don't find out later they won't cover the loss.