Travertine
Travertine (CaCO3)
sedimentary
Category
Synthetic (Not A Rock Or Mineral)
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Basalt
Mafic Igneous Rock (composed primarily of pyroxene and calcium-rich plagioclase)
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Granite
Intrusive Igneous Rock
igneous
Plume Agate
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Gneiss
Gneiss (Metamorphic rock)
metamorphic
Quartz Crystal
Silicon Dioxide (SiO2)
mineral
Granite
Granite (composed of Quartz, Feldspar, and Mica)
igneous
Quartz Geode
Quartz (Silicon Dioxide - SiO2) within a Chalcedony and Limonite shell
sedimentary
Mica Schist
Schist (Crystalline metamorphic rock)
metamorphic
Granite (likely weathered quartz-bearing granite)
Granite; primarily quartz, feldspar, and mica/amphibole
igneous
Vesicular basalt (possibly amygdaloidal basalt)
Basalt, chiefly plagioclase feldspar and pyroxene, with possible olivine and secondary mineral infillings
igneous
Sandstone
Arenite (primarily SiO2 - Silicon Dioxide)
sedimentary
Olivine in Basalt (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4 (Mineral) / Scoriaceous Basalt (Host Rock)
igneous
Quartz Pebble (with Iron Staining)
Crystalline Silicon Dioxide (SiO2)
mineral
Dyed Agate Slice
Silicon Dioxide (SiO2)
mineral
Clear Quartz Crystal (Herkimer Diamond style)
Silicon Dioxide (SiO2)
mineral
Banded Agate (Polished Slice)
Chalcedony (cryptocrystalline Quartz), SiO2
mineral
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Muscovite Schist
Muscovite Schist (KAl2(AlSi3O10)(OH)2 matrix)
metamorphic
Diorite
Diorite (Intermediate intrusive igneous rock)
igneous
Quartz
Silicon Dioxide (SiO2)
mineral
Greenstone / Diorite
Intermediate plutonic igneous rock
igneous
River Cobble (Gneiss/Schist mix)
Foliated Metamorphic Rock (Gneissic/Schistose)
metamorphic
Schist
Mica schist, likely muscovite–biotite schist with quartz and feldspar
metamorphic
Granite fragment
Felsic intrusive igneous rock; mainly quartz, alkali feldspar, plagioclase, and minor biotite/hornblende
igneous
Bauxite
Aluminum ore (mixture of gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH))
sedimentary
Bauxite
Bauxite (Mixture of Al(OH)3, AlO(OH), and Fe2O3)
sedimentary
Sandstone with Iron Staining
Arenite (SiO2 with Fe2O3)
sedimentary
Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Shark Tooth Fossil
Vertebrate fossilized tooth
fossil
Clear quartz sphere
Quartz (silicon dioxide, SiO₂)
mineral
Granite
Felsic intrusive igneous rock
igneous
Gabbroic rock, possibly hornblende gabbro
Gabbro; coarse-grained mafic silicate rock dominated by plagioclase and pyroxene, with possible hornblende and magnetite
igneous
Sandstone
Sedimentary Rock (Quartz Arenite)
sedimentary
Polished basalt (likely vesicular basalt)
Basalt; predominantly plagioclase, clinopyroxene, and commonly olivine or iron-titanium oxides
igneous
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) within Metasedimentary or Igneous matrix
mineral
Iron Concretion
Ferruginous concretion (Fe2O3·nH2O / FeO(OH))
sedimentary
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Granite
Intrusive Igneous Rock
igneous