Big Island does have beaches of various kinds. My favorite is (well, hard to pick) the Green Sand Beach. It is the Papakolea beach near the southernmost point of Big Island.
This is actually a partially broken cinder cone where ocean came in. The sand is actually green; as the grains are actually Olivine crystals which is green in color.
Here is a close up:
It is bit of a hike to get there, about 3 miles. It’s very popular and locals gives you a ride too in their truck. But unfortunately they don’t follow any rules and the path is fairly rutted due to numerous tire marks on the dirt. So I prefer walking. Trust me it is gorgeous when you get there and the sand is really green.
Disclaimer: All photographs are my own. Just ask me please if you like to use and share; citing the source is fine.