Man Made Composite (Lithified Equivalent Of Sedimentary)

Chert

Chert (Microcrystalline Quartz)

Flint or chert

Microcrystalline quartz (SiO₂), commonly called flint when dark and nodular

Flagstone paving (likely sandstone or limestone)

Clastic sandstone or carbonate limestone; exact identification requires testing

Chert

Microcrystalline Quartz (SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Oyster Shell (Aragonite/Calcite)

Calcium Carbonate (CaCO3)

Calcite-rich limestone

Limestone, primarily calcite (CaCO₃), possibly fossiliferous or dolomitic

Sandstone

Arenite (primarily SiO2)

Granite Sand (Decomposed Granite)

Grus / Quartz-Feldspar Detritus

Favosites (Honeycomb Coral Fossil)

Favosites sp. (Phylum Cnidaria, Order Tabulata)

Fossiliferous Limestone (Crinoidal Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Conglomerate

Conglomerate (Rock composed predominantly of rounded clasts > 2mm)

Quartz Conglomerate

Quartz Conglomerate (clastic sedimentary rock)

Crinoid Fossil

Crinoidea (Echinodermata)

Worn quartz-rich pebble, likely chert or quartzite

Microcrystalline quartz (SiO₂), possibly quartzite

Conglomerate

Conglomerate (clastic sedimentary rock)

Conglomerate

Conglomerate (clastic sedimentary rock)

Conglomerate

Conglomerate (clastic sedimentary rock)

Blue chalcedony cabochon (probable)

Chalcedony, a cryptocrystalline variety of quartz; silicon dioxide, SiO₂

Ferruginous Sandstone with Quartz Inclusions

Clastic Sedimentary Rock (Iron-rich Sandstone)

Ironstone Concretion

Siderite or Hematite Concretion

Sandstone (specifically Picture Sandstone or Wonderstone)

Arenite (composed primarily of SiO2)

Polished fossiliferous limestone pebble

Fossiliferous micritic limestone, chiefly calcite (CaCO₃)

Crinoid Fossil Limestone

Crinoidal Limestone (Calcite / CaCO3)

Sandstone (likely Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Asphalt (Bituminous Pavement Bit)

Bitumen-bound aggregate (Petrochemical-bound composite)

Sandstone

Arenite

Tumbled reddish-brown pebble, likely sandstone or iron-rich quartzite

Probable ferruginous sandstone (quartz-rich; SiO₂ with iron oxides), possibly quartzite

Turquoise

Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Fossiliferous limestone, possibly an oyster or other bivalve fossil

Calcite (CaCO₃) shell material preserved in micritic limestone; exact fossil taxon cannot be confirmed from one image

Granite (phaneritic background) with Limestone/Calcite carving

Felsic Igneous Plutonic Rock (background) / Calcium Carbonate (CaCO3) (carving)

Conglomerate

Conglomerate (Detrital sedimentary rock)

Banded iron formation (iron-rich metamorphic rock)

Banded iron formation (BIF), chiefly hematite/magnetite with chert or quartz (Fe₂O₃/Fe₃O₄ and SiO₂)

Tiger Iron

Tiger Iron (composite of Tiger's Eye, Red Jasper, and Hematite)

Cobalt Glass Slug (Man-made Glass)

Amorphous Silica with Cobalt Oxide (SiO2 + CoO)

Man-made Metal Pin (Non-geological)

Antimony-Lead Alloy or Zinc/Brass Base with Electroplating

Sandstone

Arenite

Fossiliferous limestone

Calcite-rich limestone (CaCO₃), containing possible fossil or peloidal inclusions

Weathered limestone or calcitic fossil/reef fragment

Calcite-rich limestone (CaCO₃), possibly fossiliferous limestone

Fossilized Gastropod in Chert/Limestone

Internal mold of Gastropoda (Class) with CaCO3 or SiO2 mineral formula

Grey Chalcedony

Silicon Dioxide (SiO2)