Banded iron formation fragment (likely hematite–magnetite ironstone)
Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and microcrystalline quartz (SiO₂)
sedimentary
Category
Synthetic Material (Not A Rock Or Mineral)
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Likely quartz-rich rock fragment
Probably microcrystalline quartz (SiO₂), possibly a pale chert or quartzite fragment
mineral
Sandstone (Water-worn Pebble)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Granite Pebble (Salt and Pepper Granite)
Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Biotite/Amphibole)
igneous
Quartzite / Iron-stained Chert
Silicon Dioxide (SiO2) with Iron Oxide impurities
metamorphic
Granodiorite Pebble
Granodiorite
igneous
Green Quartzite / Quartz Pebble
SiO2 (Silicon Dioxide with inclusions)
metamorphic
Siltstone Pebble
Siltstone (composed of siliciclastic grains)
sedimentary
Septarian Nodule Segment (Turtle Stone)
Septarian Concretion (CaCO3 with Siderite or Calcite infill)
sedimentary
Polished ocean jasper (orbicular jasper), probable
Microcrystalline quartz (SiO₂), chiefly chalcedony with iron-oxide and other mineral inclusions
mineral
Tumbled amber-colored chalcedony or jasper
Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper
mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (Common Opal/Agatized Rock)
Microcrystalline Quartz (SiO2) with potential Chalcedony/Opaline silica
sedimentary
Sandstone (Quartz Sandstone)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone (Quartzose / Feldspathic Sandstone)
Arenite (SiO2 principal matrix)
sedimentary
Travertine (Tufa)
Chemical Sedimentary Limestone (CaCO3)
sedimentary
Sandstone (Ferruginous)
Arenite (Fe-bearing Clastic Sedimentary Rock)
sedimentary
Fossilized ammonite (likely weathered ammonite cross-section)
Ammonoidea; commonly Jurassic–Cretaceous ammonite fossils replaced by calcite or aragonite
fossil
Shale
Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)
sedimentary
Botryoidal chalcedony (gray agate/jasper-like silica)
Microcrystalline quartz, SiO₂; likely chalcedony with opaque quartz or jasper inclusions
mineral
Granodiorite
Granodiorite
igneous
Breccia
Clastic Breccia (General mineral composition depends on fragments, often SiO2 or CaCO3)
sedimentary
Lepidodendron Fossil (Scale Tree)
Lepidodendron
fossil
Diorite (Polished Tumble)
Diorite (Intermediate intrusive igneous rock)
Igneous
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Fire Agate
Silicon Dioxide (SiO2) with Goethite or Limonite inclusions
mineral
Conglomerate (or Breccia)
Clastic Sedimentary Rock (Conglomeratic)
sedimentary
Biotite Schist
Biotite Mica Schist (K(Mg,Fe)3AlSi3O10(OH,F)2)
metamorphic
Chert (Flint)
Silicon dioxide (SiO2)
sedimentary
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Red Sandstone
Arenite (primarily Quartz SiO2 with Hematite Fe2O3 cement)
sedimentary
Malachite
Malachite — Cu₂CO₃(OH)₂, hydrated copper carbonate
mineral
Asphalt (Road Aggregate)
Bituminous Conglomerate / Asphalt Concrete
Anthropogenic (Man-made)
Sandstone (with possibly iron oxides and other minerals)
Sandstone
Sedimentary rock
Diorite (Spotted or Dalmatian Stone pattern)
Diorite
igneous
Iron-stained quartz-rich rock, likely quartzite or silicified breccia
Quartz (SiO₂), possibly quartzite with limonite/goethite iron oxides
metamorphic
Weathered quartz-rich river cobble, possibly quartzite
Quartzite (mostly microcrystalline SiO₂), tentatively identified
metamorphic
Vesicular Basalt (Amygdaloidal)
Vesicular Basalt (Fe-Mg rich extrusive volcanic rock)
igneous
Sandstone
Clastic Sedimentary Rock (composed mostly of SiO2)
sedimentary
Sandstone (Banded)
Clastic Sedimentary Rock (primarily SiO2)
sedimentary
Diorite (or Gabbro/Gneiss stream pebble)
Diorite
igneous
Schist (Greenschist / Mica Schist)
Foliated Metamorphic Rock (rich in chlorite, muscovite, and quartz)
metamorphic