Rare earth element
|Light aluminium-scandium alloy is used for aerospace components.  It is also an additive in certain lamps.<ref name="CRC_ed89_elements">C.R. Hammond, "Section 4; The Elements", in CRC Handbook of Chemistry and Physics, 89th edition (internet version 2009), David R. Lide, ed. CRC Press/Taylor and Francis, Boca Raton, FL.</ref>