Agate
Silicon dioxide (chalcedony variety), SiO2
sedimentary
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Potassium Feldspar (Microcline)
KAlSi3O8
mineral
Quartzite
Metamorphosed Quartz Sandstone
metamorphic
Basalt (Worn Cobble / Artifact)
Aphanitic Extrusive Igneous Rock
igneous
Granite
Felsic intrusive igneous rock
igneous
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Amethyst Cluster
Silicon Dioxide (Quartz variety: Amethyst) - SiO2
mineral
Petrified Wood
Silicified wood (primarily quartz, SiO2)
fossil
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Basalt Pebble
Extrusive Igneous Rock
igneous
Hematite
Iron(III) oxide (Fe2O3)
mineral
Limonite Ironstone
Goethite-Limonite concretion / Iron oxide
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Dinosaur Fossil Tooth
Vertebrate Fossilized Tooth
fossil
Blue Apatite
Apatite (Ca5(PO4)3(F,Cl,OH))
mineral
Limonite or Ironstone Concretion
FeO(OH)·nH₂O (Hydrated iron oxide-hydroxide)
mineral
Turquoise
Hydrated copper aluminum phosphate, CuAl6(PO4)4(OH)8·4H2O
mineral
Basalt
Mafic extrusive igneous rock
igneous
Green Aventurine
Quartz with fuchsite inclusions (SiO2)
mineral
Granite
Felsic intrusive igneous rock
igneous
Sandstone
Clastic sedimentary rock (primarily quartz arenite)
sedimentary
Sandstone
Clastic Sedimentary Rock
sedimentary
Chert / Flint Arrowheads and Artifacts
Cryptocrystalline quartz (SiO2)
sedimentary
Conglomerate
Sedimentary Conglomerate
sedimentary
Pumice
Pumice (Volcanic Rock)
igneous
Limestone
Calcium carbonate (CaCO3)
sedimentary
Emerald in Matrix
Beryl (Be3Al2(SiO3)6) embedded in schist or pegmatite host rock
mineral
Botryoidal Chalcedony / Quartz
Silicon Dioxide (SiO2)
mineral
Basalt
Extrusive Igneous Rock
igneous
Limestone (Weathered / Limonite-stained)
Sedimentary carbonate rock (CaCO3)
sedimentary
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Dragonstone (Brecciated Basalt/Diabase with Epidote and Quartz)
Brecciated mafic igneous rock
igneous
Geode
Quartz / Chalcedony nodule
sedimentary
Granite
Intrusive Igneous Rock
igneous
Calcite (Honey Calcite and Agate)
Calcium Carbonate (CaCO3)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Basalt
Extrusive Igneous Rock
igneous
Fossilized Shark Tooth
Chondrichthyes tooth
fossil
Quartzite Pebble
Metamorphic Quartzite (SiO2)
metamorphic
Limestone (fossiliferous)
Calcium Carbonate (CaCO3)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartzite
Quartzite (Metamorphic Quartz Arenite)
metamorphic