Yes, LUTECIUM is a Scrabble word!

Letter values in Scrabble US: L 1, U 1, T 1, E 1, C 3, I 1, U 1, M 3.

Is it a valid word?

LUTECIUM is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a trivalent metallic element of the rare earth group; usually occurs in association with yttrium

Also: atomic number 71.

Not playable in Scrabble US: LU.