Organic Mineral

Sandstone (likely Arkose or Quartz Sandstone)

Arenite (SiO2 principal component)

Geode (unopened)

Chert / Chalcedony Geode (SiO2)

Graphite

Graphite (Native Carbon), Formula: C

Dendritic Agate / Moss Agate

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

Moss Agate

Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with dendritic inclusions

Bituminous Coal (with Anthracite or Vitrinite inclusion)

Organic-rich Sedimentary Rock (Carboniferous classification)

Amber

Fossilized Tree Resin (Generic formula roughly C10H16O)

Glauconitic Sandstone

Glauconitic Quartz Arenite

Ironstone Concretion

Siderite or Hematite Concretion

Pearl

Calcium carbonate (CaCO3) + organic conchiolin (Biogenic Mineral)

Fossilized Sand Tiger Shark Tooth

Carcharias taurus / Striatolamia macrota (mineralized as Hydroxylapatite/Francolite)

Amber

Succinite (fossilized resin)

Moss Agate

Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)

Amber

Fossilized Tree Resin (C10H16O)

Yellow Chert (Jasper)

Silicon Dioxide (SiO2)

Jasper with Agate and Quartz Inclusions

Silicon Dioxide (SiO2) - Chalcedony / Quartz aggregate

Chert (concretionary/nodular variant)

Microcrystalline Quartz (SiO2) with possible fossil or mineral inclusions

Black Jasper

Black Jasper (Silicate mineral - SiO2)

Pink Opal

Amorphous Hydrous Silica (SiO2·nH2O)

Pink Opal

Hydrated Silica (SiO2·nH2O)

Petrified Wood (Silicified Wood)

Silicified fossil wood (SiO2)

Ironstone Concretion / Limonite Node

Goethite and Limonite (FeO(OH) nH2O)

Chert (Yellow Jasper/Flint)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (primarily Chalcedony or Quartz, SiO2)

Fossilized Coral

Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)

Shale (with minor calcite veining)

Clastic sedimentary rock (primarily clay minerals and quartz)

Pyrite in Shaly Matrix

Iron Sulfide (FeS2)

Chert (with Limestone and Iron Oxide staining)

Cryptocrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2 - Silicon Dioxide)

Chert (Brecciated Chert)

Silicon Dioxide (SiO2)

Chert Nodule (Fossiliferous Chert)

Microcrystalline Quartz (SiO2)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxides

Moss Agate

Chalcedony (SiO2) with inclusions of manganese or iron oxides

Chert with Quartz Veining

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Chert (Flint Nodules)

Microcrystalline Quartz (SiO2)

Chert (Flint variety)

Chert (SiO2)

Chert (varieties include Flint and Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Petrified Wood

Silicified Wood (primarily SiO₂ / Silicon Dioxide)

Petrified Wood

Silicified Wood (primarily Chalcedony or Quartz, SiO2)

Petrified Wood

Silicified Wood (SiO2)