High Quality Content by WIKIPEDIA articles! The general formula for nambulite is (Li,Na)Mn4Si5O14(OH). It is named after the mineralogist, Professor Matsuo Nambu (1917- ) of Tohoko University, Japan, who is known for his research in manganese minerals. The mineral was first discovered in the Funakozawa Mine, northeastern Japan, a metasedimentary manganese ore.