Yes, ZINCS is a Scrabble word!

Letter values in Scrabble US: Z 10, I 1, N 1, C 3, S 1.

Is it a valid word?

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

a bluish-white lustrous metallic element; brittle at ordinary temperatures but malleable when heated; used in a wide variety of alloys and in galvanizing iron; it occurs naturally as zinc sulphide in zinc blende

Also: atomic number 30.

Not playable in Scrabble US: ZN.