I've built a wooden house and decided that, with the proper precautions, I would like a fireplace. I built a stone-brick-and-glass cage around a piece of netherrack, but when I lit it, the fire still spread to the rest of the house. I've replaced the burnt part of the house, and I have a piece of glowstone in the fireplace, but I would still like to have actual fire in my fireplace. I you tell me where fire can spread, I can probably figure out how to aesthetically keep it from spreading, or else scrap the idea. Any ideas?
Most common are: Fire can burn wood and leaves. I recommend having a brick house with no wood items around your fire place, like Crafting Tables, Pistons, Fence, ect.
Fire can spread a distance of up to one block downwards, one block sideways (including diagonals), and four blocks upwards of the original fire block (not the block the fire is on/next to)
Almost anything you think can catch fire, can. Stone or stone bricks are easy to make and can easily be a good decision in replace for wood.
This source is useful in regards to fire: http://minecraft.gamepedia.com/Fire