These samples of bannisterite are displayed in the Smithsonian Museum of Natural History. Bannisterite is a silicate which contains manganese and has the composition KCaMn₂₁(Si,Al)₃₂O₇₆(OH)₁₆12H₂O. This sample is about 11 cm wide and is from Franklin, New Jersey.

This sample of bannisterite is about 5 cm long. It is from Broken Hill, New South Wales, Australia.