What is "kankite"

n. (context mineralogy English) A monoclinic yellow green mineral containing arsenic, hydrogen, iron, and oxygen.

Kankite is a mineral with the chemical formula Fe As O·3.5( HO). Kankite is named for the locality that yielded first specimens Kaňk, Czech Republic. Kankite forms in old (1200- to 1400-year-old) mine dumps. It is yellowish-green on fresh exposure, with a paler greenish yellow on exposure to air.