Sandstone
Arenite (primarily SiO2)
Category
Browse organic (paper and cellulose) specimens identified by the Rock Identifier community.
Sandstone
Arenite (primarily SiO2)
Mica (Muscovite)
Muscovite (KAl2(AlSi3O10)(OH)2)
Marble
Recrystallized Calcite (CaCO3)
Garnet Schist
Almandine Garnet Schist (Fe3Al2(SiO4)3 in Schistose matrix)
Grey Banded Agate
Chalcedony (Silicon Dioxide, SiO2)
Petoskey Stone
Hexagonaria percarinata
Agate (Geode nodule)
Cryptocrystalline Quartz (SiO2)
Graphite
Graphite (C)
Gypsum Wallboard (Drywall)
Hydrous calcium sulfate (CaSO4·2H2O)
Banded Agate (with Quartz Geode Center)
Silicon Dioxide (SiO2)
Sandstone (Water-worn Cobble)
Arenite (variable composition, primarily SiO2)
Orthoceras Fossil in Limestone
Orthoceras regulare
Mica
Phlogopite or Biotite group (KMg3(AlSi3O10)(F,OH)2 / K(Mg,Fe)3AlSi3O10(OH)2)
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 cement)
Petoskey Stone (Fossilized Rugose Coral)
Hexagonaria percarinata (Calcium Carbonate, CaCO3)
Kaolinite (Chalky Clay)
Kaolinite (Al2Si2O5(OH)4)
Pyrite
Iron Disulfide (FeS2)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Quartz River Cobble
Silicon Dioxide (SiO2)
Muscovite
Muscovite (KAl2(AlSi3O10)(OH)2)
Agate Geode Node
Cryptocrystalline Quartz (SiO2)
Dyed Purple Agate
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Fossilized Coral (Petoskey-like or Favosites)
Anthozoa (Fossilized Coral)
Thunderegg (specifically a Jasper/Agate-filled Geode nodule)
Silicon Dioxide (SiO2) within Rhyolitic Matrix
Sandstone
Arenite (primarily Quartz, SiO2)
Slate
Foliated Metamorphic Rock
Quartz with Mica (Schist/Pegmatite fragment)
Silicon Dioxide (SiO2) with Phyllosilicates (KAl2(AlSi3O10)(OH)2)
Sandstone
Arenite (primarily SiO2)
Graphite
Graphite (Native Carbon, C)
Petoskey Stone
Hexagonaria percarinata
Fossilized Coral (Petoskey-style)
Hexagonaria percarinata (Fossilized Rugose Coral)
Honey Calcite
Calcium Carbonate (CaCO3)
Aragonite (Banded Calcite / 'Mexican Onyx')
Aragonite (Calcium Carbonate - CaCO3)
Sandstone (Pet Rock)
Clastic sedimentary rock (primarily SiO2)
Garnet in Schist (Polished Tower)
Almandine Garnet (Fe3Al2(SiO4)3) in Mica Schist
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Banded Agate (specifically Sardonyx or Carnelian Agate)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Muscovite Mica (Golden/Yellow variety)
KAl2(AlSi3O10)(F,OH)2
Sandstone (with biological crust)
Arenite (SiO2 based)