Sedimentary Rock (Specifically A Concretion Or Possibly A Geode)

Quartz Geode/Cluster

Quartz (SiO2)

Fossil Coral

Scleractinia (fossilized calcium carbonate)

Chert (specifically Flint or Jasper-Chert)

Silicon Dioxide (SiO2)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Agate (Chalcedony)

Cryptocrystalline Silica or Silicon Dioxide (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Pumice (specifically a water-worn, weathered variety)

Vesicular volcanic glass

Quartz Geode

Quartz (Silicon Dioxide, SiO2) Geode

Quartz Geode (Smoky Quartz)

Silicon Dioxide (SiO2)

Druzy Quartz on Agate/Chert

Silicon Dioxide (SiO2)

Milky Quartz Geode with Chlorite

Silicon Dioxide (SiO2) with Chlorite group inclusions

River Rock (likely Siltstone or fine-grained Sandstone)

Clastic Sedimentary Rock

Limestone (specifically Fossiliferous or Crinoidal Limestone)

Calcium Carbonate (CaCO3) - Calcite Rock

Quartz (possibly milky quartz or quartz with inclusions)

SiO2 (Silicon Dioxide)

Pyrite Geode (Sparkling Druzy)

Iron Sulfide (FeS2) in Sedimentary Nodule

Quartz Geode

Silicon Dioxide (SiO2)

Jasper (Zebra Jasper)

Silicon Dioxide (SiO2) with impurities

Fossiliferous Limestone with Brachiopod Mold

Calcium Carbonate (CaCO3) matrix containing Brachiopoda fossil impressions

Clear Quartz Crystal

Quartz (Silicon Dioxide, SiO2)

Granite

Phaneritic plutonic rock (approx. 20-60% quartz, 35-90% feldspar)

Conglomerate with Quartz Inclusions

Conglomerate (clastic sedimentary rock) with internal Quartz (SiO2)

Quartz

Silicon dioxide (SiO2)

Chert Pebble/Nodule

Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Serpentine

Antigorite/Lizardite (Mg,Fe)3Si2O5(OH)4

Conglomerate

Conglomerate (Detrital Sedimentary Rock)

Chert (specifically Flint)

Microcrystalline quartz (SiO2)

Orca Agate (Blue Chalcedony)

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Septarian Nodule (Dragon Stone)

Septarian Concretion (CaCO3 - Calcite, Aragonite, and Limestone/Clay)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Limonite Concretion

Limonite (FeO(OH)·nH2O)

Sandstone (specifically Arkose or Ferruginous Sandstone)

Sandstone (SiO2 with iron oxide inclusions)

Amethyst

Amethyst (SiO₂)

Amethyst (Geode)

Silicon Dioxide with Iron impurities (SiO2)

Conglomerate (or Breccia)

Clastic Sedimentary Rock

Banded Agate (Onyx variety)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Ironstone Concretion (Siderite Nodules)

Siderite (FeCO3) in Mudstone or Sandstone matrix

Bumble Bee Jasper

Calcite-bearing Volcanic Tuff (not a true Jasper)

Orange Calcite

Calcium Carbonate (CaCO3)

Carnelian

Carnelian (Silicon Dioxide - SiO2)