Kaolinite (Kaolin)
Kaolinite (Al2Si2O5(OH)4)
mineral
Category
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Sandstone (Wonderstone)
Arenite (composed primarily of SiO2 with Fe2O3 impurities)
sedimentary
Banded Sandstone
Arenite with Liesegang banding (primarily SiO2 with FeO(OH) impurities)
sedimentary
Optical Calcite (Iceland Spar)
Calcite (Calcium Carbonate, CaCO3)
mineral
Pyrite (Fool's Gold)
Iron Pyrite (FeS2)
mineral
Tumbled agate/chalcedony
Microcrystalline quartz (SiO₂), likely agate or jasper-bearing chalcedony
mineral
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
fossil
Marble
Metamorphosed Limestone (principally CaCO3)
metamorphic
Petoskey Stone (Fossilized Rugose Coral)
Hexagonaria percarinata
fossil
Banded Agate (specifically Carnelian Agate)
Silicon Dioxide (SiO2)
mineral
Quartzite River Cobble
Quartzite (dominated by SiO2)
metamorphic
Tumbled agate (likely Botswana or fortification agate)
Microcrystalline quartz, SiO₂ (chalcedony with banded impurities)
mineral
Graphite-rich schist (probable graphite ore)
Graphite schist; chiefly graphitic carbon (C) with quartz, mica, and possibly feldspar
metamorphic
Limestone with Calcite Crystals
Calcium Carbonate (CaCO3)
sedimentary
Limestone
Sedimentary Rock (Primarily Calcite: CaCO3)
sedimentary
Porphyritic Diabase (Porphyry)
Porphyritic Diabase / Microgabbro
igneous
Banded Gneiss
Gneiss (quartz-feldspar-biotite metamorphic rock)
metamorphic
Puddingstone (Conglomerate)
Conglomerate (clastic sedimentary rock)
sedimentary
Almandine Garnet
Almandine, Fe3Al2(SiO4)3
mineral
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Rounded river cobble, likely weathered sandstone or quartz-rich metasandstone
Indeterminate sandstone; commonly quartz (SiO₂) with feldspar, lithic grains, and iron-oxide cement
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Calcite
Calcium Carbonate (CaCO3)
mineral
Banded Agate
Cryptocrystalline Quartz (SiO2)
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Jasper (specifically Owyhee or Picture Jasper variety)
Jasper (Silicon Dioxide, SiO2)
sedimentary
Talc
Talc (Hydrated magnesium silicate, Mg3Si4O10(OH)2)
metamorphic
Chalk
Calcium Carbonate (CaCO3)
sedimentary
Petoskey Stone
Hexagonaria percarinata
fossil
Rounded granitic cobble
Granite or granitic gneiss; primarily quartz, feldspar, and mica
igneous
Polished agate geode
Chalcedony (microcrystalline quartz, SiO₂) with quartz druse crystals
mineral
Puddingstone (Quartzite Conglomerate with Jasper inclusions)
Metaconglomerate (Silicon Dioxide, SiO2)
sedimentary
Fossil Rugose Coral (Horn Coral)
Order Rugosa (likely Grewingkia or Heliophyllum species); Calcium Carbonate (CaCO3)
sedimentary
Ironstone Concretion
Siderite or Hematite Concretion (FeCO3 or Fe2O3)
sedimentary
Sandstone with Quartz Vein
Arenite with Quartz (SiO2) Infilling
sedimentary
Puddingstone
Conglomerate (typically quartz-rich or jasper-rich)
sedimentary
White Marble
Metamorphic Limestone (CaCO3)
metamorphic
Dyed Quartz Geode
Silicon Dioxide (SiO2) with artificial pigment
mineral
Muscovite Mica
Muscovite: KAl2(AlSi3O10)(OH)2
mineral
Slate
Foliated Metamorphic Rock (primarily composed of quartz, illite, chlorite, and micas)
metamorphic