aluminium amphibole android artificial intelligence astronomy clay crystallization diagenesis diatom epidote exoskeleton feldspar fractionation geology ligand melting metamorphic rock metamorphism meteorite mica mineral mineralogy moon octahedron olivine oxygen planet planetary nebula plankton polymer pyroxene quartz science fiction sediment silicate minerals silicon silicon dioxide stishovite tetrahedron thaumasite tourmaline weathering zeolite