Yes, tufa is a Scrabble word!
...and is worth 7 points in Scrabble, and 8 points in Words with Friends
tufa
Noun
1. A soft porous rock consisting of calcium carbonate deposited from springs rich in lime
2. Hard volcanic rock composed of compacted volcanic ash
What Scrabble words can I make with the letters in tufa?
3 Letter Words
2 Letter Words