Lava Rock to Pebbles - South Kona Hawaii

This is the start of what's called Pebble Beach in South Kona Hawaii. It's wave action on the lava rocks that knocks off a piece. The piece tumbles around in the ocean that smooths its sharp edges. The smooth pieces get smaller and smaller as parts of it are slowly taken off by the ocean action. Then the waves carry the pebbles and throws them onto the shore forming Pebble Beach.