Coal
Coal was one of the gift items during Holiday 1997.
Coal ingots were initially created by smelting the piles of coal from the 1997 "Naughty" Christmas Bag. Coal ingots are a slightly different shade of color than Shadow ingots.
Some players were able to collect enough Coal ingots to create sets of armor now commonly referred to as Coal Armor. Depending on the age of the crafter markings, these old sets of coal armor can be extremely valuable.