Man Made Composite (Lithified Equivalent Of Sedimentary)

Sandstone Concretion

Sedimentary concretion

Sandstone

Arenite

Water-worn sandstone pebble

Quartz-rich sandstone (likely arkosic or ferruginous sandstone)

Weathered gray sandstone or fine-grained metamorphic rock

Likely quartz-rich sandstone (quartz arenite), possibly weakly metamorphosed metasandstone

Fossiliferous Chert or Limestone

Sedimentary rock containing fossilized marine invertebrates (likely crinoid stems or bryozoans)

Rounded river pebble, likely weathered limestone or sandstone

Indeterminate carbonate or siliciclastic sedimentary rock; likely limestone (calcite-rich, CaCO₃) or lithic sandstone

Fossiliferous Limestone

Biogenic Limestone (CaCO3)

Fossilized Brachiopod

Phylum Brachiopoda (Calcium Carbonate/Silica replacement)

Tumbled brown-and-cream stone, likely jasper or chert

Microcrystalline quartz (SiO₂), probably jasper/chert; exact identification requires testing

Sandstone

Arenite (primarily SiO2)

Likely weathered chert or siliceous limestone fragment

Microcrystalline quartz (SiO₂), possibly with calcite (CaCO₃)

Weathered chert or siliceous limestone

Microcrystalline quartz (SiO₂), possibly replacing or cementing carbonate rock

Red-brown sandstone or iron-rich weathering fragment

Quartz-rich sandstone, likely hematite/goethite-stained; exact identification requires testing

Weathered fossiliferous limestone, possibly coral or stromatoporoid

Calcitic limestone, predominantly CaCO₃; fossil identity cannot be confirmed from one photograph

Sandstone

Arenite

Weathered reddish sandstone pebble

Quartz-rich sandstone (composition varies; commonly SiO₂-dominated clastic rock)

Fossilized Coprolite

Coprolite (fossilized feces)

Likely weathered fossil-bearing limestone

Calcareous sedimentary rock, primarily calcite (CaCO₃); fossil identity uncertain from the image

Conglomerate

Clastic Sedimentary Rock (Conglomerate)

Fossil Shark Tooth

Lamniform (Mackerel Shark) fossil tooth, likely Otodus or Cretalamna

Fossiliferous limestone slab

Bioclastic limestone, chiefly calcite (CaCO₃), with possible shell or coral fragments

Weathered gray rock fragment

Likely quartz-rich sandstone or weakly metamorphosed sandstone; exact identification is uncertain from the photograph

Layered shale or mudstone fragment

Fissile claystone/mudstone, commonly clay minerals with quartz and minor iron oxides

Weathered chert or chalcedony nodule

Microcrystalline quartz (SiO₂), possibly silicified limestone or agate-like chalcedony

Reddish quartz-rich rock, possibly jasper or chert

Microcrystalline quartz (SiO₂), likely iron-oxide-stained jasper/chert

Sedimentary Breccia

Clastic Breccia (CaCO3/SiO2 matrix)

Polished fossiliferous limestone

Bioclastic carbonate rock, primarily calcite (CaCO₃)

Weathered graywacke or sandstone fragment

Lithic sandstone, likely quartz–feldspar–rock-fragment aggregate

Rounded river pebble (likely weathered sandstone or chert)

Indeterminate clastic sedimentary rock; possible quartz-rich sandstone

Weathered limestone or calcitic fossil-bearing rock

Calcite-rich limestone, primarily CaCO₃

Crushed limestone gravel

Limestone; predominantly calcite (CaCO₃), possibly dolomitic limestone with dolomite (CaMg(CO₃)₂)

Fossiliferous Limestone (Pink/Red)

Calcium Carbonate (CaCO3) with Bioclasts

Fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃)

Weathered iron-rich sandstone or ironstone nodule

Ferruginous sandstone; primarily quartz (SiO₂) cemented or stained by iron oxides/hydroxides such as hematite and goethite

Tumbled tan pebble, likely sandstone or chert

Uncertain; probable quartz-rich sandstone (SiO₂-bearing)

Blue slag glass or dyed glass-like industrial material

Amorphous silicate glass; likely copper-bearing blue slag, but possibly colored man-made glass

Sandstone (Quartzose)

Arenite (composed primarily of SiO2)

Brachiopod Fossil in Limestone

Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)

Sandstone (likely Arkosic)

Clastic Sedimentary Rock (primarily SiO2 with Feldspar)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Quartz-rich feldspathic rock, possibly granite or arkose

Granite-like aggregate of quartz (SiO₂), feldspar, and minor iron oxides