The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. Graphite has a metallic luster and a silvery-gray color. It is very soft (H = 1), has a slick, greasy feel, and readily marks paper. Graphite does have cleavage, but it is not apparent at the hand specimen scale. The ability of graphite to mark paper, its softness, and its greasy feel are all a consequence of cleavage sheets easily slipping over each other on a microscopic scale.
Graphite (4.2 cm across)