Yes, GRAVIES is a Scrabble word!

Letter values in Scrabble US: G 2, R 1, A 1, V 4, I 1, E 1, S 1.

Is it a valid word?

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

a sauce made by adding stock, flour, or other ingredients to the juice and fat that drips from cooking meats
the seasoned but not thickened juices that drip from cooking meats; often a little water is added
a sudden happening that brings good fortune (as a sudden opportunity to make money)

Also: pan gravy, gold rush, manna from heaven.

Not playable in Scrabble US: BUNCE.