Porphyritic Basalt or Amygdaloidal Basalt
Porphyritic Extrusive Igneous Rock
igneous
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Amethyst Cluster
Silicon Dioxide (Quartz variety: Amethyst), SiO2
mineral
Granite
Felsic intrusive igneous rock
igneous
Epidote
Epidote (Ca2(Al, Fe)3(SiO4)3(OH))
mineral
Epidote or Unakite Rock
Epidote-bearing rock / Ca2(Al,Fe)3(SiO4)3(OH)
metamorphic
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Agate
Chalcedony (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony replacing $SiO_2$)
sedimentary
Limonite Nodule
FeO(OH)·nH2O (Hydrated iron oxide-hydroxide)
mineral
Limonite with Gold-bearing Quartz
Hydrated Iron Oxide Hydroxide, FeO(OH)·nH2O
mineral
Fossil Coral
Scleractinia (Fossilized Hexacoral)
fossil
Magnetite
Fe3O4 (Iron(II,III) oxide)
mineral
Magnetite
Iron(II,III) oxide (Fe3O4)
mineral
Basalt River Stone
Extrusive Igneous Rock
igneous
Olivine (Peridot)
(Mg,Fe)2SiO4
mineral
Vesicular Basalt / Scoria pebble
Extrusive igneous rock with amygdaloidal infilling
igneous
Green Jasper Pebble
Microcrystalline Quartz (SiO2) with impurities
sedimentary
Sandstone
Quartz arenite / Lithic sandstone
sedimentary
Jasper
Microcrystalline quartz (SiO2)
sedimentary
Sandstone
Sedimentary Rock (Quartz arenite / Lithic sandstone)
sedimentary
Sandstone
Sedimentary Rock (Quartz arenite / Lithic sandstone)
sedimentary
Basalt with Vesicular/Amygdaloidal Alteration
Extrusive Igneous Rock (Mafic)
igneous
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Green Aventurine
Quartz (SiO2) with fuchsite inclusions
mineral
Limonite (Goethite/Ironstone)
Hydrated iron oxide-hydroxide, approximately FeO(OH)·nH2O
mineral
Malachite
Copper Carbonate Hydroxide (Cu2CO3(OH)2)
mineral
Jasper and Mudstone Composite
Silicified Sedimentary Rock / Jasperoid Pebble
sedimentary
Granite
Felsic intrusive igneous rock
igneous
Red and White Quartzite
Metamorphic Quartz Sandstone (SiO2)
metamorphic
Jasper in Calcite / Brecciated Jasper
Silicon dioxide with calcium carbonate (SiO2 with CaCO3)
sedimentary
Jasper
Silicon Dioxide (SiO2) with impurities, microcrystalline quartz
sedimentary
Jasper
Silicon Dioxide (Microcrystalline Quartz), SiO2
sedimentary
Granite
Felsic intrusive igneous rock
igneous
Megalodon Shark Tooth
Otodus megalodon
fossil
Granite
Intrusive Igneous Rock
igneous
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Sandstone (Weathered Fragment)
Clastic Sedimentary Rock
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral