Diamond Beach. a key element of Vatnajokull National Park, is a well-known south coast Iceland black sand beach named for the glistening icebergs (the "diamonds") deposited on it. After melting and floating in nearby Jokulsarlon Glacier Lagoon (see Gallery), the icebergs drift out to the ocean where they are polished prior to the wind and current bringing them to this amazing place of natural wonder.