Very fine-grained, generally sooty graphite from metamorphosed coalbeds.
The word amorphous is a misnomer because all graphite is crystalline. The
term has also been applied to very fine particles of flake graphite that
can be sold only for low-value uses (such as foundry facings), and to
fine-grained varieties of Ceylon lump graphite. AGI
Source: Dictionary of Mining, Mineral, and Related Terms