Habit: massive granular grains. Color: brown to reddish brown and black. Luster: vitreous to greasy. Diaphaneity: translucent to opaque. Cleavage: (001) and (100). Fracture: conchoidal. Streak: grayish-brown. Occurrence: near-end members rare and
only intermediate members are found in volcanic rocks but they are commonly found in
metallurgical slags and synthetic products.
