First you'll be taken by its dramatic location on a solid river of black lava, then you'll be knocked for six by the dazzling turquoise bay it's named for, and by the time you're lounging on the massive deck attached to the best cottages, you'll be deadset on extending your stay. Swimming and white-sand sunning is superb; check out the lava pool at high tide.
The restaurant means well, but is very hit-or-miss; if you're driving, there's an excellent pizza place five minutes up the road.