Bannisterite

(Ca,K,Na)(Mn²⁺,Fe²⁺)₁₀(Si,Al)₁₆O₃₈(OH)₈·nH₂O

Bannisterite is rare at Broken Hill, but has produced some exceptional specimens. It occurs as dark brown to black platy crystals in aggregates up to 20cm across.

Selected Australian Occurrences:

• North Mine, Broken Hill, New South Wales.
• Zinc Corp Mine, Broken Hill, New South Wales.