Sedimentary (Fossiliferous)

Polished fossiliferous limestone, possibly coral or shell fossil

Calcite-rich limestone (CaCO₃), with probable fossilized skeletal structures

Weathered sandstone or quartz-rich sedimentary pebble

Indeterminate lithic fragment; likely quartz arenite (sandstone)

Polished fossiliferous limestone (likely orbicular/fossil limestone)

Fossiliferous micritic limestone, composed primarily of calcite (CaCO₃)

Banded limestone or marble

Calcite-dominated carbonate rock; likely banded marble (CaCO₃)

Banded chert or siliceous sedimentary rock

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide staining and possible carbonate/clay layers

Light-gray weathered stone, likely limestone

Calcite-rich limestone (CaCO₃), possibly calcareous sandstone or concrete-like rock

Weathered limestone or calcareous concretion

Calcite-rich carbonate rock; chiefly calcium carbonate (CaCO₃)

Fossiliferous wood / petrified wood fragment

Silicified or partially mineralized wood (fossil wood; commonly quartz/chalcedony replacement)

Weathered iron-rich sandstone or ironstone

Ferruginous sandstone; likely quartz-rich sandstone cemented or stained by iron oxides (hematite/goethite)

Likely weathered limestone

Calcite-rich carbonate rock; primarily calcium carbonate (CaCO₃)

Weathered sandstone fragment

Quartz-rich clastic sandstone, likely ferruginous sandstone

Rounded limestone pebble

Micritic limestone, primarily calcite (CaCO₃)

White limestone

Calcite-dominated carbonate rock (CaCO₃), possibly chalky limestone

Chert or flint (weathered brown variety)

Microcrystalline quartz, SiO₂ (chalcedonic quartz)

Rounded pebble, likely limestone

Microcrystalline calcite (CaCO₃), probably micritic limestone

Weathered sandstone fragment

Clastic sandstone, likely quartz-rich (quartz arenite or arkose)

Limestone

Calcium Carbonate (CaCO3)

Likely weathered sandstone fragment

Quartz-rich sandstone, predominantly SiO₂ with minor feldspar and iron-oxide cement

Weathered sandstone or quartz-rich rock fragment

Indeterminate siliciclastic sandstone; primarily quartz (SiO₂) with feldspar and iron-oxide cement

Weathered sandstone

Quartz-rich clastic sandstone, likely iron-oxide stained

Weathered limestone

Limestone, predominantly calcite (CaCO₃)

Likely weathered sandstone or iron-stained sedimentary fragment

Quartz-rich sandstone; exact identification requires testing

Tumbled, weathered limestone or calcareous concretion

Calcite-rich limestone; predominantly calcium carbonate (CaCO₃)

Limestone

Calcium Carbonate (CaCO3)

Fossiliferous limestone pebble (probable coral or shell fossil)

Calcite (CaCO₃), commonly biogenic limestone; exact fossil taxon indeterminate from the image

Weathered sandstone or iron-stained limestone fragment

Likely quartz-rich sandstone (SiO₂) or calcitic limestone (CaCO₃); exact identification requires testing

Likely fossiliferous limestone fragment

Calcareous fossil assemblage, chiefly calcium carbonate (CaCO₃), possibly crinoid, bivalve, or bryozoan material in limestone

Fossiliferous Sandstone / Quartzite Pebble

Sedimentary rock with skeletal fragments (e.g., Paleozoic crinoid/brachiopod fossils)

Likely weathered limestone or marble fragment

Calcite-rich carbonate rock; likely limestone (CaCO₃), possibly recrystallized marble

Likely weathered limestone or calcareous tuff

Calcite-rich carbonate rock, chiefly CaCO₃; exact identification is uncertain from the image

Limestone

Calcium Carbonate (CaCO3)

Likely limestone or chalky carbonate rock

Calcite-rich limestone; predominantly calcium carbonate (CaCO₃)

Weathered limestone

Calcite-rich carbonate rock; predominantly CaCO₃

Weathered limestone or calcitic fossil-bearing rock

Calcite-rich limestone, primarily CaCO₃

Glauconitic Sandstone (Greensand pebble)

Glauconitic Quartz Sandstone (K(Fe,Al)2(Si,Al)4O10(OH)2)

Porous limestone (likely fossiliferous or weathered limestone)

Calcite-rich limestone; chiefly calcium carbonate (CaCO₃)

Fossiliferous Limestone (Coral Fossil)

Calcium Carbonate (CaCO3) with Colonial Coral inclusions

Flint / Chert (or fossiliferous nodule)

Microcrystalline quartz (SiO2)

Fossiliferous Chert (Brachiopod/Bryozoan Fossil)

Microcrystalline quartz (SiO2) with fossil inclusions

Fossiliferous Limestone

Calcium carbonate matrix with macrofossils (CaCO3)

Red sandstone

Quartz arenite or ferruginous sandstone, composed mainly of quartz (SiO₂) with iron-oxide cement

Crushed Limestone

Calcite-rich Sedimentary Rock (CaCO3)