Sandstone Cobble
Arenite (Secondary classification based on grain size)
sedimentary
Category
Organic (Paper And Cellulose)
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Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Granite
Phaneritic intrusive igneous rock
igneous
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Polished fossiliferous limestone, likely crinoidal or coral limestone
Calcite (CaCO₃), fossiliferous carbonate rock
fossil
Banded Agate (specifically shades of Carnelian Agate)
Silicon Dioxide (SiO2)
mineral
Polished basalt with a quartz vein
Basalt, cut by milky quartz (SiO₂)
igneous
Pyrite
Iron Disulfide (FeS2)
mineral
Porphyry
Porphyritic Andesite/Dacite
igneous
Porphyritic Basalt (Flowerstone)
Porphyritic Basalt (Mafic volcanic rock)
igneous
Pyrite
Iron Sulfide (FeS2)
mineral
Conglomerate
Conglomeratic Sandstone / Polymictic Conglomerate
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Agate
Silicon Dioxide (SiO2) - Banded Chalcedony
mineral
Granite (with Quartz and Mica)
Phaneritic Felsic Igneous Rock
igneous
Quartzite
Quartzite (SiO2)
metamorphic
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Granite Cobble
Felsic intrusive igneous rock (composition: SiO₂ with KAlSi₃O₈, NaAlSi₃O₈, and CaAl₂Si₂O₈)
igneous
Pyrite
Iron Sulfide (FeS2)
mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Tumbled blue quartzite or blue chalcedony (uncertain)
Quartz-rich rock; predominantly silicon dioxide (SiO₂)
metamorphic
Agate (various color varieties)
SiO₂ (Silicon Dioxide)
Mineral (specifically a variety of Chalcedony, which is a microcrystalline quartz)
Polished blue calcite sphere (tentative identification)
Calcite, CaCO₃; blue color generally results from trace impurities or inclusions
mineral
Polished white chalcedony or milky quartz pebble
Chalcedony, microcrystalline quartz (SiO₂), possibly with iron-oxide staining or a minor mineral inclusion
mineral
Polished black stone egg, probably black obsidian
Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements
gemstone
Talc
Talc (Mg₃Si₄O₁₀(OH)₂)
Mineral
Clay (as a rock-forming material)
Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)
Mineral
Seashell Fragment
Calcium carbonate (CaCO3) - primarily Aragonite or Calcite
fossil
Black Onyx and Mother of Pearl
Cryptocrystalline Quartz (SiO2) and Nacre (Calcium Carbonate)
mineral
Marble
Marble (primarily Calcite, CaCO3 or Dolomite, CaMg(CO3)2)
Metamorphic Rock
Agate
Agate (a variety of Chalcedony, SiO2)
Mineral
Agate
Agate (a cryptocrystalline variety of Quartz, SiO₂)
Mineral
Turquoise and Red Coral
CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Corallium rubrum (Red Coral)
mineral
Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin, CaCO3
gemstone
Amber
Succinates (Fossilized Resin)
mineral
Pearl and Garnet Glass
Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass
mineral and glass
Calcite
Calcite (CaCO₃, Calcium Carbonate)
Mineral
Petrified Wood
Petrified Wood (Silicified Wood)
fossil
Amber / Copal
Organic resin, C10H16O
mineral
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite
mineral