Not A Rock (Man Made Polymer)

Pumice

Pumice (Vesicular Rhyolite/Andesite)

Shale

Shale (Lutite)

Vesicular Basalt (or Scoria)

Vesicular Basalt (Aphanitic-vesicular volcanic rock)

Pink Quartzite

Quartzite (SiO2 with minor iron oxide impurities)

Green Aventurine

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

Sandstone Cobble

Clastic Sedimentary (Sandstone)

Chert / Chalcedony (likely carnelian or flint variety)

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate rock

Mexican Crazy Lace Agate

Silicon Dioxide (SiO2) with iron and aluminum inclusions

Quartz (Rock Crystal) with minor impurities

Quartz (SiO2)

Quartz (Druzy on Matrix)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (Siliclastic Sedimentary Rock)

Basalt

Mafic extrusive volcanic rock (composed primarily of Plagioclase feldspar and Pyroxene)

Porphyry

Porphyritic Rock

Conglomerate

Conglomerate rock

Milky Quartz with Country Rock contact

Silicon Dioxide (SiO2) in contact with Metamorphic/Igneous rock

Shale

Argillaceous Rock

Agate Geode

Silicon Dioxide (SiO2) - Chalcedony / Quartz Variety

Vesicular Basalt

Basalt with vesicular texture

Yellow Quartzite

Quartzite (SiO2 with iron oxide inclusions)

Peridotite (Pyroxenite/Serpentinized Dunite)

Ultramafic Rock (consisting primarily of Olivine and Pyroxene)

Gneiss

High-grade metamorphic rock (Gneiss)

Puddingstone (Gowganda Tillite/Jasper Conglomerate)

Jasper Conglomerate (SiO2 primary composition)

Sandstone (specifically Banded Sandstone)

Clastic sedimentary rock (primarily SiO2)

Sandstone or Limestone

Arenite or Calcareous Sedimentary Rock

Granodiorite

Granodiorite (containing Plagioclase, Quartz, and Biotite)

Glacial Cobble (likely Granitic or Gneissic)

Granite/Gneiss Glacial Erratic

Quartz (Milky/Crystalline)

Silicon Dioxide (SiO2)

Quartz Geode

Quartz (Silicon Dioxide - SiO2) within a Chalcedony and Limonite shell

Schist

Mica Schist (Medium-grade Metamorphic Rock)

Limonite (after Pyrite Pseudomorph)

Limonite (Hydrated Iron Oxide Mixture, FeO(OH)·nH2O)

White Topaz

Aluminum Silicate Fluoride Hydroxide; Al2SiO4(F,OH)2

Limestone (specifically Travertine or Tufa)

Calcium Carbonate (CaCO3)

Crushed Stone (Basalt/Gabbro)

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Agate (Common Chalcedony)

Silicon Dioxide (SiO2)

Granite

Phaneritic Plutonic Igneous Rock (primarily composed of quartz, alkali feldspar, and plagioclase)

Massive Quartz with Host Rock

Silicon Dioxide (SiO2)

Concretion

Various mineral compositions, typically carbonate or iron oxide cemented sediment

Sandstone (Iron-stained)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

Agate Geode with Quartz Druzy

Chalcedony (SiO2) and Quartz (SiO2)

Amethyst

Silicon Dioxide (SiO2) with Iron impurities