b om ite ▁super group . ▁The ▁other ▁constitu ents ▁of ▁the ▁n iger ite ▁group ▁are ▁fer ron iger ite - 6 N 6 S , ▁mag nes ion iger ite - 2 N 1 S , ▁mag nes ion iger ite - 6 N 6 S , ▁z in con iger ite - 2 N 1 S ▁and ▁z in con iger ite - 6 N 6 S . ▁The ▁ 2 N 1 S ▁ending ▁stands ▁for ▁the ▁n olan ite ▁and ▁spin el ▁struct ural ▁layers . ▁ ▁Fer ron iger ite - 2 N 1 S ▁was ▁first ▁discovered ▁in ▁the ▁Kab ba ▁prov ence ▁of ▁central ▁Niger ia ▁in ▁ 1 9 4 4 ; ▁it ▁was ▁originally ▁named ▁Niger ite . ▁Its ▁name ▁was ▁later ▁changed ▁to ▁n iger ite - 6 H ▁then ▁to ▁n iger ite - 6 T ▁and ▁in ▁ 2 0 0 3 ▁fer ron ig ert ie - 2 N 1 S ▁was ▁approved ▁by ▁the ▁International ▁Min eral og ical ▁Association . ▁ ▁Chem ical ▁composition ▁ ▁The ▁general ▁chemical ▁formula ▁of ▁fer ron ig ert ie - 2 N 1 S ▁is ▁( Z n , M g , Fe 2 + )( S n , Z n ) 2 ( Al , Fe 3 +) 1 2 O 2 2 ( OH ) 2 ▁or ▁Sn ( Fe , M g ) Al 6 O 1 1 ( OH ). ▁ ▁Its ▁percent ▁composition ▁is ▁ 5