It would be nice if they included zoomed out pictures as well, is hard to tell what the beaches look like in person from the magnified sand.

If you click into one of the examples they have a photo of a hand holding a sample plus photos of the beach.

Well, here's a video which ends with a hand holding a sample.[1] It's a sand-making plant. Big rocks go in, and repeated crushing makes them into sand-sized rocks.

[1] https://www.youtube.com/watch?v=lVBiRPkQ0MI