Walking to the lava flow viewing areas near Kilauea and to the Kalapana black sand beaches you walk across fields of ropey, slowly crumbling pāhoehoe. Everything has melted, flowing into uneven lumps and whorls of dense black rock. The twists and turns cable their way across the slowly undulating landscape, disappearing in cracks or in the broken roofs of lava tubes. Close up the pāhoehoe shines, an iridescent silver black. There's glass in here, the molten silicates of the basalt crystallising out as the rock slowly cools.
Soon it too will be sand.