Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Chert (specifically Novaculite or Porcelainite)

Microcrystalline to Cryptocrystalline Quartz (SiO2)

Fossil Coral

Scleractinia (Anthos), primarily Calcium Carbonate (CaCO3)

Tumbled jasper, likely red/brown jasper

Microcrystalline quartz (chalcedony), SiO₂, colored by iron oxides

Petrified Wood

Silicified Wood (Permineralized organic matter, głównie $SiO_2$)

Fossilized Gastropod in Limestone

Gastropoda (Class) in Fossiliferous Limestone

Quartz Pebble

Silicon Dioxide (SiO2)

Weathered chert or siliceous limestone

Microcrystalline quartz (SiO₂), possibly with carbonate minerals

Chert (Pink Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Chert (Commonly known as Flint)

Microcrystalline Quartz (SiO2)

Chert (White/Gray variety)

Chert (SiO2)

Jasp-Agate

Cryptocrystalline Quartz (SiO2) with Iron Oxide inclusions

Pyrite (on host rock)

Iron Sulfide (FeS2)

Bivalve Fossil (Clam/Mollusk)

Class: Bivalvia (Order: Veneroida), Calcium Carbonate (CaCO3)

Fossilized Brachiopod

Brachiopoda (e.g., Atrypa or Rhynchonellida)

Tumbled brown translucent stone, likely quartz/jasper

Microcrystalline quartz (SiO₂), possibly iron-stained chalcedony or jasper

Gneissic Schist

Foliated Metamorphic Rock (Schist/Gneiss transition)

Chert Pebble

Chert (composed primarily of Microcrystalline Quartz, SiO2)

Shale or Siltstone

Sedimentary Clastic Rock (Variable mineral composition including quartz and clay minerals)

Hematitic Sandstone

Sandstone with Iron Oxide (Hematite) staining

Brecciated quartz-rich rock, possibly silicified breccia

Silica-rich breccia; chiefly microcrystalline quartz (SiO₂), with possible calcite and iron-oxide staining

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Laterite

Laterite (Iron- and aluminum-rich rock)

Conglomerate (River Rock)

Clastic sedimentary rock (primarily SiO2)

Blue chalcedony cabochon (probable)

Chalcedony, cryptocrystalline quartz; silicon dioxide (SiO₂)

Fossiliferous limestone (likely ammonite/gastropod-bearing)

Bioclastic limestone; predominantly calcite (CaCO₃)

Bumblebee Jasper

Travertine (Calcite/Aragonite) with Realgar, Pyrite, and Volcanic Ash

Polished brecciated jasper

Silicified breccia, chiefly microcrystalline quartz (SiO₂) with iron-oxide staining

Orbicular rhyolite (likely)

Rhyolite, a silica-rich volcanic rock; commonly quartz, alkali feldspar, plagioclase, and iron-rich alteration minerals

Jasper Conglomerate (Puddingstone)

Jasper Conglomerate (Siliceous Sedimentary Rock)

Petrified Wood

Silicified Wood (Silicon Dioxide - SiO2)

Flint Arrowhead

Cryptocrystalline quartz (Chert/Flint, SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Weathered iron-rich rock, likely limonite-bearing sandstone or laterite

Limonite/goethite-rich ferruginous rock; composition commonly FeO(OH)·nH₂O with quartz and clay minerals

Polished red gemstone pendant, likely red jasper or brecciated jasper

Jasper: microcrystalline quartz (SiO₂), commonly with hematite or iron-oxide inclusions

Rounded gray-brown river pebble

Indeterminate lithic clast; likely weathered sandstone or fine-grained metamorphic rock

Jasper Conglomerate (Puddingstone)

Siliceous Conglomerate (Quartz and Jasper clasts in a fine-grained matrix)

Chert (Iron-stained Flint / Jasper)

Microcrystalline Quartz (SiO2) with Iron Oxides

Red jasper (likely iron-rich chert)

Microcrystalline quartz (SiO₂) colored by hematite/goethite

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Nodule)

Cryptocrystalline Quartz (SiO2)

Weathered gray rock fragment

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

Calcite

Calcium Carbonate (CaCO3)