A traditional holiday threat by both exasperated parents and sly Secret Santas, A Lump of Coal is what you'll find in your stocking if you weren't a good little boy this year. Or girl. Or even goblin.
Typically found as a roughly fist-sized lump, A Lump of Coal is similar to the somewhat more polyhedral popular dice used in many RPGs, except that it doesn't matter which side winds up on top when you roll it. But hey, you can always use it for heating.
A Lump of Coal can be found in versions ranging from matte black to dull gray.
Coal is a combustible black sedimentary rock usually occurring in layers or veins called coal seams. Throughout history, coal has been used as an energy resource, primarily by dwarves and gnomes. Most human use is confined to industrial purposes, such as refining metals - especially for masterwork weapons. Elves hate coal pollution and refuse to contemplate its use as an energy source. Many humanoids use coal when it is available - in some regions, it also is known as a major component of hill giant diets. Burning coal has been demonstrated as highly effective in the destruction of trolls and many other regenerative creatures and further investigations in this area are warranted.