Rock (Likely Sedimentary)

Chert (specifically Red Chert or Jasper)

Microcrystalline Quartz (SiO2)

Banded Agate

Agate (Cryptocrystalline Quartz, SiO2)

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Formation

Quartz Vein / Milky Quartz

Silicon Dioxide (SiO2)

Aragonite / Calcite Geode

Calcium Carbonate (CaCO3)

Marble (White)

Metamorphosed Limestone (mainly CaCO3)

Banded Siltstone or Argillite

Siltstone (primarily SiO2 with Al and Fe oxides)

Petrified Wood

Silicified Wood (primarily Quartz/Chalcedony, formula: SiO2)

Geode with Quartz/Chalcedony

Silicon Dioxide (SiO2)

Sandstone (specifically Red Sandstone)

Arenite (primarily Quartz, SiO2)

Chalcedony (Botryoidal Agate vein)

Chalcedony (Microcrystalline Quartz) - SiO2

Calcite Geode

Calcium Carbonate (CaCO3)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (primarily SiO2 with Fe2O3)

Banded Sandstone (Liesegang Rings)

Sedimentary Arenite (SiO2 with FeO/Fe2O3 impurities)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Limestone (specifically Fossiliferous Limestone)

Calcium Carbonate (CaCO3)

Red Sandstone (Hematitic)

Clastic sedimentary rock (SiO2 with Fe2O3 inclusions)

Gneiss

Gneiss (High-grade Metamorphic Rock)

Concretion (Sandstone)

Carbonate-cemented Sandstone Concretion

Quartz Druzy on Geode Fragment

Silicon Dioxide (SiO2)

Sandstone

Arenite (Siliclastic sedimentary rock, primarily SiO2)

Fancy Jasper (Ocean Jasper or River Jasper variant)

Silicon Dioxide with inclusions (SiO2)

Sandstone (Pebble/Cobble)

Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)

Bored Siltstone (Holey Rock)

Siltstone with Pholad borings (Lithophaga/Pholadidae trace fossils)

Sandstone

Arenite (composed primarily of SiO2)

Fossil Shell Fragment (possibly Brachiopod or Bivalve)

Calcium Carbonate (CaCO3) - Phylum Brachiopoda or Mollusca

Quartz Pebble

Silicon Dioxide (SiO2)

Schist

Mica Schist (Metamorphic Rock)

Limonitic Iron Ore / Goethite

Hydrated Iron(III) oxide-hydroxide (primarily FeO(OH)·nH2O)

Sandstone

Arenite (composed primarily of SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Chert / Flint Nodules in Limestone

Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)

Bauxite

Bauxite (Mixture of Hydrous Aluminum Oxides)

Clear Quartz / Rock Crystal

Silicon Dioxide (SiO2)

Peridot (likely, based on color and appearance)

Olivine group mineral, specifically (Mg,Fe)2SiO4 (Forsterite-Fayalite solid solution series)

Druzy Quartz (on Chalcedony/Agate base)

Silicon Dioxide (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Fossilized Coral (Coquina/Limestone)

Cnidaria Anthozoa (Fossilized)

Red Jasper (Polished)

Silicon Dioxide (SiO2) with Hematite inclusions

Banded Agate (Tumbled)

Agate (Variety of Chalcedony/Quartz), SiO2

Quartz Geode

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)