Yes, PITCHBLENDES is a Scrabble word!

Letter values in Scrabble US: P 3, I 1, T 1, C 3, H 4, B 3, L 1, E 1, N 1, D 2, E 1, S 1.

Is it a valid word?

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

a mineral consisting of uranium oxide and trace amounts of radium and thorium and polonium and lead and helium; uraninite in massive form is called pitchblende which is the chief uranium ore