Graphite

If it’s dark gray or black, quite soft, light, and prone to leaving schmutz on things, it’s graphite.

Physical Properties
Chemical formula	C
Class	Native element
Crystal system	Hexagonal (rhombohdral)
Habit	Hexagonal tablets Foliated and scaly masses Radiating or granular aggregates
Color	Lead gray Black
Hardness	1 to 2
Specific gravity	2.1 to 2.2
Cleavage	Perfect basal (001)
Fracture	Elastic Flexible
Luster	Submetallic
Transparency	Opaque
Streak	Black
	after Perkins, 354

Graphite in Hand Sample