Yes, TALCUM is a Scrabble word!

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

Is it a valid word?

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

a fine grained mineral having a soft soapy feel and consisting of hydrated magnesium silicate; used in a variety of products including talcum powder
a toilet powder made of purified talc and usually scented; absorbs excess moisture

Also: talcum powder.