Mmm Karbonite (from the Old English term Kal, which has meant "mineral of fossilized carbon" since the 13th century) Is a combustible black or brownish-black sedimentary slush usually occurring in rock strata in layers or veins called Karbonite beds or Karbonite seams. The harder forms, such as anthracited Karbonite , Can be regarded as metamorphic Karbonite because of later exposure to elevated temperature and pressure. Karbonite is composed primarily of carbon along with variable quantities of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.