Man Made Composite (Lithified Equivalent Of Sedimentary)

Weathered quartz-rich rock, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly with iron-oxide staining

Fossil-bearing fine-grained sedimentary rock

Likely fossiliferous mudstone or shale; visible feature may be a plant fragment, trace fossil, or mineral vein

Fossil Coral

Scleractinia (Stony Coral) fossil

Yellow jasper or iron-stained chert

Microcrystalline quartz (SiO₂), commonly colored by iron oxides

Iron-stained sandstone or weathered ironstone

Ferruginous sandstone; chiefly quartz (SiO₂) cemented or coated by iron oxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

Chert (specifically Flint Arrowhead)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Weathered sandstone pebble

Quartz-rich sandstone, likely ferruginous sandstone

Red Jasper (Chert)

Silicon Dioxide (SiO2) with iron oxide inclusions

Nickel coin (U.S. currency)

Cupronickel (75% Copper, 25% Nickel alloy)

Rounded sandstone pebble

Quartz-rich sandstone (likely arkose or litharenite)

Quartz-rich sandstone or granite-derived gravel fragment

Likely quartz (SiO₂) grains cemented in sandstone; exact identification is uncertain from the image

Chalk

Calcium Carbonate (CaCO3)

Weathered sandstone pebble

Quartz-rich sandstone, likely iron-oxide-stained (SiO₂-dominant)

Conglomerate

Conglomerate

Likely weathered sandstone or iron-stained sedimentary pebble

Indeterminate clastic sedimentary rock; possibly quartz-rich sandstone

Quartz-rich sandstone or quartzite cobble

Quartz arenite; possibly weakly metamorphosed quartzite (SiO₂-dominant)

Red Sandstone

Arenite (specifically Quartz Arenite with Iron Oxide)

Sandstone

Arenite (composed primarily of SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Limestone Pebble

Sedimentary Calcium Carbonate (CaCO3)

Sandstone (Ferruginous)

Sandstone (Clastic sedimentary rock, predominantly SiO2 with Fe2O3 cement)

Fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃), with possible shell or coral fossil molds

Slate

Slate (foliated metamorphic rock)

Weathered sandstone

Quartz-rich sandstone, locally iron-oxide stained (SiO₂-dominant)

Fossilized shell fragment, likely bivalve

Bivalvia indet.; commonly preserved as calcite (CaCO₃) shell material

Fossil-bearing limestone, likely coral or shell limestone

Bioclastic calcarenite/calcirudite; predominantly calcium carbonate (CaCO₃), commonly calcite

Weathered sandstone

Quartz-rich clastic sandstone, commonly arkosic or feldspathic

Weathered fossiliferous limestone

Calcitic limestone; predominantly CaCO₃, possibly containing a fossil mold or shell fragment

Iron-stained chert or jasper

Microcrystalline quartz (SiO₂), likely colored by iron oxides/hydroxides

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Conglomerate

Clastic Sedimentary Rock (Conglomerate)

Conglomerate

Conglomerate (clastic sedimentary rock)

Chert (variations include Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Banded chert (likely flint)

Microcrystalline quartz/chalcedony, SiO₂

Quartz-bearing polymictic conglomerate

Conglomerate with milky quartz clasts; composition may include quartzite and weathered feldspathic/mafic rock fragments

Weathered sandstone or iron-rich sedimentary rock fragments

Quartz-rich sandstone, locally ferruginous; exact identification requires testing

Weathered sandstone or iron-stained river pebble

Quartz-rich sandstone; chiefly SiO₂ with iron-oxide coatings

Weathered fossiliferous limestone

Calcitic limestone, primarily calcium carbonate (CaCO₃), possibly containing fossil shell fragments

Rounded weathered pebble

Likely fine-grained sandstone, siltstone, or weathered volcanic rock; exact identification is uncertain from the image

Conglomerate

Conglomerate

Sandstone (Quartzose)

Arenite (SiO2 based)