As in making a lump of coal??? How about get your basic shape in a dark grey create a new layer above it and create a clipping mask and use a lighning brush or crak brush and put random strokes on top of the coal in a fiery red/ orange colour. Then go to layer blending options apply a bevel and emboss with depth set all the way to 100% method chisel hard (or whichever you like the best then adjust other sliders to what suits it best. next go to inner glow and outer glow settings and set the colour for a warm\hot glow. Then go back to your coal shape layer and add the glow settings as well and maybe to finish it off paint some light grey vertical lines above the oblect on a new layer and distort it into s shape style add a gaussian blur to it to replicate a kind of heat wave lower the opacity. and then use a steam or smoke brush very faintly to replicat smoke or steam. Just at the top of my head.
is this kind of what you want? It's multiple steps but very easy. It could be made to glow more but I wanted to get the idea out first, and I'm sorry the glowing parts between the coals weren't carefully done but like I said... wait to find out if meets your criteria.