Ironstone (possibly Bog Iron or Limonite)
Goethite-rich Ironstone (FeO(OH))
sedimentary
Category
Antropogenic (Man Made Industrial Byproduct)
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Iron Meteorite (Oxidized)
Iron-Nickel Alloy (Fe, Ni)
meteorite
Sandstone
Arenite (composed primarily of Quartz: SiO2)
sedimentary
Bornite
Bornite (Cu5FeS4)
mineral
Wollastonite
Calcium Inosilicate Mineral, CaSiO3
mineral
Fossilized echinoid (sea urchin), likely a flint/chalk-associated test
Echinoid fossil; likely a regular echinoid such as Echinocidaris or related taxon, composed mainly of recrystallized calcite (CaCO₃)
fossil
Diabase (Dolerite)
Diabase / Dolerite
igneous
Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Green glassy slag or manufactured glass bead
Noncrystalline silicate glass; likely industrial glass/slag, not a true mineral
mineral
Land Snail Shell
Gastropoda (Calcium Carbonate, CaCO3)
fossil
Iron Slag
Anthropogenic Ferro-silicate
mineral
Bicolor Quartz (Milk Quartz with Slag or Dark Inclusions)
Silicon Dioxide (SiO2) with impurities
mineral
Likely quartz fragment
Quartz (silicon dioxide, SiO₂)
mineral
Iron Meteorite / Limonite-coated Meteorite / Iron Nodule
Iron-Nickel Alloy (Kamacite and Taenite) with weathering crust
meteorite
Sandstone
Arenite
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Quartzite
Metamorphic Quartz Sandstone
metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
sedimentary
Jasper
Silicon dioxide (SiO2) with impurities
sedimentary
Obsidian (Black)
Obsidian (High-silica volcanic glass)
igneous
Quartzite
Metamorphic Rock (Mainly SiO2)
metamorphic
Diabase (Greenstone)
Diabase (Dolerite)
igneous
Iron-rich meteorite candidate
Unclassified iron meteorite or stony-iron meteorite; confirmation requires chemical and nickel testing
meteorite
Sandstone
Arenite
sedimentary
Diamond (Pear Cut)
Carbon (C)
gemstone
Cupronickel (on a 1981 Mexico 20 Pesos coin)
Copper-Nickel Alloy (Cu75Ni25)
mineral
Quartz-lined vesicle in basalt (amygdaloidal basalt)
Amygdaloidal basalt with drusy quartz; predominantly plagioclase, pyroxene, and iron oxides
igneous
Ferruginous Sandstone (Ironstone)
Clastic Sedimentary Rock (composed of SiO2 with Fe2O3/FeO(OH) cement)
sedimentary
Sandstone (specifically Arkose or Quartz Arenite)
Arenite (primarily SiO2 with possible Feldspar)
sedimentary
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Talc
Talc (Mg₃Si₄O₁₀(OH)₂)
Mineral
Weathered iron-rich rock, possibly jasper or ironstone
Likely limonite/goethite-bearing siliceous rock; exact identification requires hardness and streak tests
mineral
Red Sandstone
Arenite (with Iron Oxide / Hematite staining)
sedimentary
Chert (specifically Flint Arrowhead)
Silicon dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Uncertain polymict breccia or altered volcanic rock
Likely hydrothermally altered volcanic breccia; exact mineral identification requires testing
igneous
Chert (Yellow Jasper variant)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Dyed Blue Agate Slice
Silicon Dioxide (SiO2)
mineral
Possible tektite or volcanic glass specimen
Natural silica glass; composition commonly near SiO₂, but exact identification requires chemical testing
mineral
Banded Calcite or Travertine
Calcium Carbonate (CaCO3)
Sedimentary
Chalcedony (Agate Pebble)
Silicon Dioxide (SiO2)
sedimentary
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
sedimentary