Not A Rock

Smoky Quartz and Chalcedony Geode Fragment

Silicon Dioxide (SiO2)

Shale or Slaty Mudstone

Argillaceous sedimentary rock

Sandstone

Arenite (SiO2 dominant)

Lapis Lazuli

Lapis Lazuli (a rock type, not a single mineral, composed primarily of lazurite, calcite, and pyrite)

Garnet Schist

Garnetiferous Micaceous Schist

Basalt

Extrusive mafic igneous rock

Chert (Jasper/Flint Pebble)

Microcrystalline quartz (SiO2)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within metamorphic/igneous matrix

Painted River Pebble (likely Basalt or Greywacke)

Aphanitic Lithic Clast with Anthropogenic Pigment coating

Basalt Cobble

Vesicular Basalt (Mafic Extrusive)

Granodiorite

Granodiorite

Metaconglomerate

Metaconglomerate (Quartzite conglomerate)

Vesicular Basalt (Pumice-like)

Vesicular Basalt

Granodiorite

Granodiorite (containing Plagioclase, Quartz, and Biotite)

Serpentine

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Pink Granite

Phaneritic Felsic Intrusive Igneous Rock

Desert Rose (Baryte or Selenite variant)

Barium Sulfate (BaSO4) or Gypsum (CaSO4·2H2O) with Sand inclusions

River Rock / Stream Pebble

Fluvial Clast / Rounded Sedimentary Particle

Sandstone

Clastic sedimentary rock (primarily SiO2)

Yellow Quartzite (River Pebble)

Quartzite (SiO2)

Granodiorite (Gneissic texture)

Granodiorite (containing Quartz SiO2, Plagioclase Feldspar, and Biotite)

Basalt (Vesicular)

Basalt (Extrusive Volcanic Rock)

Geode with Quartz and possibly Jasper/Hematite

Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides

Quartz Geode

Silicon Dioxide (SiO2)

Basalt with inclusion

Basalt (Aphanitic-Porphyritic texture)

Basalt with Scoria

Amygdaloidal Basalt / Vesicular Basalt

Druzy Quartz on Chert/Chalcedony

Silicon Dioxide (SiO2)

Quartz Geode (likely within Limestone or Dolomite matrix)

Quartz (SiO₂)

Basalt

Basalt (Mafic volcanic rock)

Amber-bearing Coal/Sedimentary Rock

Bituminous coal or carbonaceous siltstone with Fossilized Tree Resin (C10H16O)

Desert Varnish on Sandstone

Ferromanganese coating on Quartz Arenite

Gneiss

High-grade regional metamorphic rock (Foliated)

Basalt

Basalt

Shale (Beach-worn)

Laminated Pelite (primarily clay minerals and quartz)

Quartzite (Yellow/Orange variety)

Quartzite (primarily SiO2)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Pebble (likely Sandstone or Granitic Pebble)

Clastic Sediment (or specific rock type, e.g., Arenite, Granitoid Pebble)

Basalt

Mafic Igneous Rock (composed primarily of plagioclase feldspar and pyroxene)

Basalt

Basalt (Mafic volcanic rock)

Basalt Cobble

Aphanitic Mafic Igneous Rock (Basalt)

Druzy Quartz on Chert/Siltstone

Silicon Dioxide (SiO2) on Microcrystalline Silica/Siltstone matrix

Sandstone (Weathered Cobble)

Clastic sedimentary rock (primarily SiO2)