This Is Not A Rock Or Mineral

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone Cobble with Iron Staining

Arenite with Limonite/Hematite staining

Quartz (Smoky/Granular variety)

Silicon Dioxide (SiO2)

Granite

Intrusive igneous rock

Quartz vein in weathered host rock

Quartz (SiO₂), likely in a weathered metamorphic or igneous matrix

Granite

Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase)

Small polished or naturally worn stone, possibly quartz-bearing rock

Indeterminate from the blurred image; likely quartz (SiO₂) or a pale feldspar-rich fragment

Pumice

Pumice (volcanic rock)

Granite

Felsic intrusive igneous rock

Granite

Felsic intrusive igneous rock

Sandstone

Arenite (SiO2 based)

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase ± pyroxene/olivine)

Sandstone

Sedimentary Rock (Quartz arenite/Arkose)

Quartz with Mica

Silicon Dioxide (SiO2) with Mica group inclusions

Smooth river pebble

Indeterminate lithology; likely fine-grained quartz-rich sandstone, siltstone, or weathered chert

Geode (Unopened)

Siliceous Geode (SiO2)

Sandstone

Arenite (primarily SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz-veined Mudstone or Argillite

SiO2 (Quartz) in Siltstone/Mudstone matrix

Granite

Intrusive Igneous Rock

Sandstone

Clastic Sedimentary Rock

Granite

Granite (Intrusive Igneous Rock)

Granite

Felsic intrusive igneous rock

Quartz-veined Limestone

Sedimentary limestone with quartz/calcite veinlets

Plume Agate or Moss Agate

Agate (SiO2)

Agate (Common Chalcedony)

Silicon Dioxide (SiO2)

Granite

Phaneritic Felsic Igneous Rock

Gravel and Pebbles

Unconsolidated rock fragments / detrital sediment

Sandstone

Sedimentary Rock (Quartz Sandstone)

Shale (Beach-worn)

Laminated Pelite (primarily clay minerals and quartz)

Calcite (or Travertine / Limestone)

Calcium Carbonate (CaCO3)

Sandstone with Quartz Vein

Arenite with SiO2 intrusion

Red Sandstone

Sedimentary Arenite / Quartzose Sandstone

Granite

Phaneritic intrusive igneous rock

Unidentified weathered mineral/rock fragment

Indeterminate; likely a weathered iron-rich silicate or sulfide-bearing specimen

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)

Ironstone Concretion (Moqui Marble / Boji Stone)

Sedimentary Iron Oxide Concretion (Fe2O3 / FeO(OH))

Unidentified gray rock/mineral specimen

Indeterminate; possibly quartz-rich rock or a metallic sulfide-bearing specimen

Druzy Quartz Geode

Silicon Dioxide (SiO2)

Sandstone (Painted)

Arenite (primarily SiO2)

Copper Ore (Malachite and Azurite on Host Rock)

Cuprite, Malachite, and Azurite dissemination in gangue