In the Lanaryu Caves, there is a "circle" of bombs with a gossip stone in the middle. If you slash some bomb to make them all explode, the stone will turn into a rocket and fly to the sky. That's standard behavior, explode a gossip stone and it will fly. No news.
What I discovered is that you can stick yourself to the stone with the whip. I didn't manage the stone to pull me up, I can only attach the whip when the stone is standing at the ground. But I strongly believe that I can attach myself to it, next time I'll try using the claws after the stone is mid-air.
After exiting the Lanaryu Caves into the Sand Sea, just after exiting the caves, before latching yourself to the columns to get to the harbor, use the beedle and try to reach the top of the tower. I did it, but the beetle's energy depleted just after passing the edge of the tower, I could see a silver rupee, but I think there is a Goddess Cube and maybe even the Sand Dragon up there.
I've got the Goddess Cube dowsing ability, next time I get there I'll use it. I really think it's quest related or something, I've found the Water Dragon before getting the first flame, why didn't the Sand Dragon appear before getting the second?