Rocks -- The rock cycle -- Earth's layers -- Rocks & weather -- Tectonic plates -- Marsquakes -- Under the sea -- Igneous rocks -- Granite -- Granite around the world -- Basalt -- Volcanoes -- Volcanologists -- Geysers & mineral springs -- Obsidian -- Tuff -- Geodes -- Rock homes -- Sedimentary rocks -- Sandstone -- Glaciers -- Limestone -- Limestone structures -- Stalactites & stalagmites -- Shale -- Landslides -- Chalk -- Tufa & travertine -- Flint -- The Stone Age -- Archaeology -- Metamorphic rocks -- Marble -- Marble in art & architecture -- Gneiss -- Florence Bascom -- Slate -- Fulgurite & tektites -- Hornfels -- Famous rocks around the world -- Rock homes, part II -- Ancient art -- Fossils -- Paleontologists -- Young paleontologists -- Petrified wood & amber -- Minerals -- Gold -- Going for the gold -- Silver -- Lost at sea -- Diamonds -- Meteorites -- Platinum -- Copper -- The Bronze Age -- Iron -- The Iron Age -- Graphite -- Minerals in the sea -- Silicates -- Clays -- Sulfides & sulfates -- Minerals & money -- Halides -- Oxides & hydroxides -- Mines of the world -- Recycling facts -- Carbonates -- Phosphates -- Organic "minerals" -- Gems -- Diamonds -- Emeralds -- Aquamarine -- Rubies & sapphires -- Crown jewels & famous collections -- Jade -- Magical & mysterious minerals -- Birthstones -- Tourmaline -- Opal -- Other popular gems -- Becoming a rock hound.