dīˈadəˌkīt noun
( -s )
Etymology: German diadochit, from Greek diadochos succeeding, relieving (from diadechesthai to succeed, relieve, from dia- + dechesthai to take, receive) + German -it -ite; akin to Latin decēre to be fitting, proper — more at decent
: a mineral Fe 2 (PO 4 )(SO 4 )(OH).5H 2 O consisting of a basic hydrous ferric phosphate and sulfate that is brown or yellowish in color