River Cobble (Basalt or Sandstone)
Weathered Basalt or Fine-Grained Sandstone
igneous
Category
Man Made (Synthetic Rock)
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Granite
Intrusive Igneous Rock
igneous
Granite Pebble
Intrusive Igneous Rock
igneous
Druzy Quartz on Host Rock
Silicon Dioxide (SiO2)
mineral
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Sedimentary or Metamorphic (low-grade)
Quartz Pebble (Geode Fragment / Druzy Cavity)
Silicon Dioxide (SiO2)
mineral
Black Limestone with Calcite Veining
Bituminous Limestone (CaCO3 with Organic Carbon inclusions)
sedimentary
Quartz (Druzy on Matrix)
Silicon Dioxide (SiO2)
mineral
Basalt
Mafic extrusive volcanic rock (composed primarily of Plagioclase feldspar and Pyroxene)
igneous
Sandstone (Ferruginous)
Sandstone (primarily SiO2 with iron oxide Fe2O3 staining)
sedimentary
Carnelian Agate / Iron-Stained Quartz
SiO2
Mineral
Druzy quartz geode
Microcrystalline quartz (SiO₂), commonly lining a volcanic geode cavity
mineral
Fossils in Limestone (Crinoid / Marine Invertebrate Fossil)
Fossiliferous Limestone (containing Crinoidea / Brachiopoda)
fossil
Limestone (Weathered Pebble)
Calcium Carbonate (CaCO3) / Limestone
sedimentary
Quartz-Veined Sandstone
Quartz-veined Arenite
sedimentary
Limestone (River Pebble)
Calcium Carbonate (CaCO3)
sedimentary
Banded Rock (likely Quartz-rich)
Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals
Mineral
Limestone (specifically Travertine or Tufa)
Calcium Carbonate (CaCO3)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Gabbro or Diorite with Quartz/Epidote Vein
Intrusive Igneous Rock (Plutonic)
igneous
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in Geodic habit
mineral
Quartz Geode with Calcite
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3)
mineral
Yellow Quartzite
Quartzite (SiO2 with iron oxide inclusions)
metamorphic
Peridotite (Pyroxenite/Serpentinized Dunite)
Ultramafic Rock (consisting primarily of Olivine and Pyroxene)
igneous
Puddingstone (Gowganda Tillite/Jasper Conglomerate)
Jasper Conglomerate (SiO2 primary composition)
sedimentary
Gneiss
High-grade metamorphic rock (Gneiss)
metamorphic
Greenstone / Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)3(Si, Al, Fe)2O5(OH)4
metamorphic
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Gneiss (Metamorphic Rock)
Gneiss (variable mineral formula primarily containing Quartz, Feldspar, and Mica)
metamorphic
Note: Item is not a geological specimen
Homo sapiens (Dermal Appendage: Pilus)
Organic / Biological
Basalt (River Pebble)
Mafic volcanic rock (rich in magnesium and iron)
igneous
Quartz Vein in Sedimentary Matrix
Silicon Dioxide (SiO2) with host rock
mineral
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
White Topaz
Aluminum Silicate Fluoride Hydroxide; Al2SiO4(F,OH)2
mineral
Sandstone (Iron-stained)
Arenite with Limonite/Hematite staining
sedimentary
Quartz Druzy (Geode Fragment)
Silicon Dioxide (SiO2)
mineral
Snakeskin Jasper
Microcrystalline Quartz (SiO2) with iron inclusions
sedimentary
Agate (Common Chalcedony)
Silicon Dioxide (SiO2)
mineral
Quartz Vein in Matrix (Breccia / Host Rock with Quartz)
Silicon Dioxide (SiO2) in Host Rock Matrix
metamorphic
Painted Rock / Geode Specimen
Silicon Dioxide with artificial pigment coating
mineral
Mexican Crazy Lace Agate
Silicon Dioxide (SiO2) with iron and aluminum inclusions
mineral