Physical properties
Habit: tabular, foliated.
Color: white, gray.
Luster: pearly, vitreous.
Diaphaneity: transparent to translucent.
Streak: white.
Cleavage: (001).
Twinning: {310}, and {001}.
Fracture: uneven, tough.
Definition
gibbsite: A mineral form of hydratedaluminium hydroxide(Al(OH)
3). It is named after the USmineralogist George Gibbs (d. 1833).
