Synthetic (Not A Rock Or Mineral)

Sandstone (Banded Sandstone)

Clastic Sedimentary Rock (primarily SiO2 with iron oxide impurities)

Porphyritic Basalt

Basalt (with plagioclase or k-feldspar phenocrysts)

Earth

Terra / Earth

Sandstone and River Pebbles

Sedimentary Rock (Sandstone / Quartzite / Chert)

Wishing Stone (Quartz-veined Porphyritic Basalt)

Igneous rock with quartz vein (SiO2)

Sandstone

Sedimentary Clastic Rock (Quartzose Sandstone)

Tumbled Amethyst

Quartz (Silicon Dioxide, SiO2, colored by iron impurities)

Quartzite Cobble / Quartz River Pebble

Silicon Dioxide (SiO2) - Quartzite / Quartz

Desert Rose (Gypsum Rose)

Gypsum (CaSO4·2H2O) with inclusions of sand

Spinifex Texture Komatiite

Komatiite (Ultramafic Volcanic Rock)

Yellow Jasper

Microcrystalline Quartz (SiO2)

Agate

Silicon Dioxide (Chalcedony), SiO2

Lazulite Quartzite

Quartzite with Lazulite (SiO2 with (Mg,Fe)Al2(PO4)2(OH)2)

Pink Mimbres Agate / Plume Agate

Silicon dioxide (SiO2) with mineral inclusions

Jasper and Epidote in Quartzite

Metamorphic rock containing microcrystalline quartz, epidote, and jasper

Sandstone Pebble

Sedimentary Rock (Quartzose Sandstone)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (SiO2 primarily)

Basalt with Quartz Veins

Mafic Igneous Rock (primarily Plagioclase and Pyroxene) with SiO2 inclusions

Epidote

Epidote ({Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH))

Red Siltstone (or Red Shale)

Clastic Sedimentary Rock (Composition: primarily Quartz, Clay minerals, and Hematite Fe2O3)

Gneiss

Gneiss

Bauxite

Bauxite (Al2O3·2H2O mixed with iron oxides)

Porphyry

Porphyritic Igneous Rock

Sandstone Concretion (Omar or Nut Rock)

Sedimentary Concretion (specifically an 'Omarolluk' or Omar)

Limonite (often after Pyrite)

Limonite (FeO(OH)·nH2O)

Banded Rock (likely Quartz-rich)

Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals

Sandstone

Arenite (SiO2 based)

Sandstone (Banded)

Clastic Sedimentary Rock: Arenite

Sandstone

Clastic Sedimentary Rock

Red Sandstone (with possible iron oxide staining)

Sandstone (primarily Quartz with Hematite/Goethite cement)

Granite

Phaneritic Felsic Igneous Rock

Dyed Dalmatian Stone

Aplite (Alkali-feldspar granite) with Arfvedsonite

Fluorite on Matrix

Calcium Fluoride (CaF2)

Sandstone

Sedimentary Rock (Quartz arenite or arkose)

Sandstone (with potential fossil fragments)

Sandstone (SiO2 dominated with iron oxides)

Biotite (Black Mica)

Biotite - K(Mg,Fe)3(AlSi3O10)(F,OH)2

Sandstone

Arenite

Sandstone

Arenite (primarily SiO2)

Turquoise

CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)

Quartz Geode

Quartz (Silicon Dioxide, SiO2) in a Geode

Sandstone

Arenite (SiO2 primarily)