Yes, LITHOPS is a Scrabble word!

Letter values in Scrabble US: L 1, I 1, T 1, H 4, O 1, P 3, S 1.

Is it a valid word?

LITHOPS is a valid word in the official Scrabble dictionary (US) and the UK Scrabble Dictionary, but not in Words with Friends (ENABLE).

any plant of the genus Lithops native to Africa having solitary yellow or white flowers and thick leaves that resemble stones

Also: living stone, stone-face, stone plant, stone life face, flowering stone.

Not playable in Scrabble US: STONEFACE.