Sandstone-based Concrete Fragment
Cementitious Composite with Sedimentary Aggregate
sedimentary (man-made/anthropogenic)
Category
Organic Material (Likely A Fruit Or Berry)
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Sandstone
Arenite (primarily SiO2)
sedimentary
Red Sandstone
Clastic sedimentary rock (Quartz arenite/Arkose)
sedimentary
Rounded quartz-rich beach pebble
Likely quartzite or quartz-rich sandstone; predominantly quartz (SiO₂)
sedimentary
Blue-dyed magnesite beads (often sold as “turquoise howlite”)
Magnesite, MgCO₃; commonly dyed blue and possibly marketed as dyed howlite, Ca₂B₅SiO₉(OH)₅
mineral
Chert (and Agate/Quartz in Geode-like Nodule)
Silicon Dioxide (SiO2)
sedimentary
Chert (Beach Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically as a lithic artifact/projectile point)
Chert (Silicon dioxide, SiO2)
sedimentary
Garnetiferous Pegmatite
Pegmatite with Almandine Garnet and Muscovite
igneous
Quartzite Chert Pebble
Microcrystalline Silicon Dioxide (SiO2)
sedimentary/metamorphic
Travertine
Calcareous tufa (CaCO3)
sedimentary
Sandstone
Arenicola (comprising mostly Quartz, SiO2)
sedimentary
Coal (Anthracite / Bituminous)
Organic Sedimentary Rock (Carbon-based)
sedimentary
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (often called Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Fossil shell fragment
Indeterminate molluscan bioclast, likely aragonite or calcite
fossil
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Granite Pebble
Granite
igneous
Chert (Flint variety)
Chert (SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Quartz/SiO2)
mineral
Black Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Fossiliferous Limestone
Limestone (CaCO3) with Crinoid/Bivalve fossils
sedimentary
Pumice (specifically a water-worn, weathered variety)
Vesicular volcanic glass
igneous
Basalt with Quartz/Feldspar Inclusions
Amygdaloidal or Porphyritic Mafic Volcanic Rock with Siliceous Veining
igneous
Chert (Yellow Jasper variant)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
metamorphic
Petrified Wood
Silicified Wood (SiO2)
mineral
Jasper
Silicon dioxide (SiO2)
sedimentary
Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Fancy Jasper
Jasper (Cryptocrystalline Quartz, SiO2)
sedimentary
Jasper
Jasper (Cryptocrystalline variety of Quartz, SiO2)
sedimentary
Granite Cobble
Phaneritic Felsic Intrusive Rock (Granite)
igneous
Tumbled jasper or chert
Microcrystalline quartz (SiO₂), possibly iron-bearing jasper
mineral
Quartz (Milky and Smoky variety)
Silicon Dioxide (SiO2)
mineral
Sandstone (Water-worn Cobble)
Arenite (variable composition, primarily SiO2)
sedimentary
Enrolled Trilobite Fossil
Phylum Arthropoda, Class Trilobita (likely Calymene or Flexicalymene)
fossil
Ammonite Fossil (Iridiscent)
Ammonoidea (subclass)
fossil
Chert (and Flint)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Jasper-bearing Quartzite River Cobble
Tectonized Quartzite with Iron-Oxide (Hematite/Limonite) Veining
metamorphic
Rugose Coral (Horn Coral) Fossil
Order Rugosa (likely Grewingkia or Zaphrentis genus)
fossil
Chert / Flint
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Pebble)
Chert (Microcrystalline Quartz, SiO2)
sedimentary