Rock (Likely Sedimentary)

Quartz-rich sandstone or quartzite fragment

Likely quartz arenite; possibly weakly metamorphosed quartzite (mostly SiO₂)

Chert (Jasper-like Silicate)

Silicon Dioxide (SiO2)

Fossilized Shark Tooth (Partial)

Elasmobranchii (fossil tooth fragment)

Conglomerate

Conglomerate (Clastic Sedimentary Rock)

Quartz Geode

Silicon Dioxide (SiO2)

Blue Chalcedony

Cryptocrystalline Quartz (SiO2)

Iron-rich concretion (probable limonite/goethite concretion)

Hydrated iron oxides, chiefly limonite (FeO(OH)·nH₂O) and goethite (FeO(OH))

Weathered iron-rich sandstone or laterite

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

Iron-rich sandstone or laterite

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

Chert (Chert breccia)

SiO2 (Silicon Dioxide)

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Coquina (Fossiliferous Limestone)

Coquina (Organic Clastic Limestone)

Banded Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or River Pebble)

Chert (Microcrystalline Quartz, SiO2)

Chert Pebble (Jasper/Quartz variety)

Microcrystalline Quartz (SiO2)

Chert (Common Variety, Jasper)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Chert (SiO2)

Brachiopod Fossil in Sedimentary Rock

Phylum Brachiopoda fossil imprint in sedimentary matrix

Gravel / Small Pebble

Rock Fragment (Gravel)

Pebble

Lithified rock fragment / Sedimentary clast

Granite (likely weathered cobble)

Granite; chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende

Fenestella Bryozoan Fossil

Fenestella (class Stenolaemata)

Tumbled jasper, likely picture or brecciated jasper

Microcrystalline quartz (SiO₂) with iron-oxide and other mineral impurities

Translucent chalcedony (likely agate or common opal)

Microcrystalline quartz, SiO₂; possible hydrated silica opal, SiO₂·nH₂O

Sandstone

Arenite

Weathered sandstone fragment

Sandstone, primarily quartz (SiO₂) with feldspar and iron-oxide cement

Fossiliferous Limestone (Gritstone/Marl)

CaCO3 (Calcium Carbonate) with Fossil Inclusions

Chert (Arrowhead Fragment)

Chert / Microcrystalline Silicon Dioxide (SiO2)

Chert (River Siltstone/Flint)

Chert (SiO2)

Chert (Basanite / Flint variation)

Chert (Silicon Dioxide, SiO2)

Granite (Weathered River Rock)

Plutonic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Quartz-rich pebble, possibly chert or silicified limestone

Microcrystalline quartz (SiO₂), possibly chalcedony; exact identification is uncertain from the photograph

Fossilized Coral

Rugose Coral / Hexagonaria (Fossilized calcium carbonate)

Cockle Shell (Bivalve)

Cardiidae (Calcium Carbonate, CaCO3)

Iron-rich sandstone or weathered ironstone

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

Iron-rich quartzite or ferruginous metamorphic rock

Quartzite, predominantly SiO₂, stained by iron oxides (hematite/goethite)

Stony-Iron Meteorite (likely Mesosiderite or Ordinary Chondrite)

Meteorite (Silicate-Metal Matrix)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz vein in weathered host rock

Milky quartz (SiO₂), likely in a granitic or metamorphic matrix

Quartz-veined Sandstone Pebble

Quartzose Sandstone with Quartz Veinlets

White quartz pebble (likely milky quartz)

Quartz, silicon dioxide (SiO₂)