Lanthanum

Lanthanum is a chemical element first isolated from a compound of cerium, which was obtained from a rare earth mineral in 1839. It is noteworthy for being named from the Greek word meaning 'hidden' due to its obscurity within those minerals.
 Carl Gustaf Mosander Sweden 1839 Lanthanum

Lanthanum is a chemical element first isolated from a compound of cerium, which was obtained from a rare earth mineral in 1839. It is noteworthy for being named from the Greek word meaning 'hidden' due to its obscurity within those minerals.