Mineral (Organic)

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

Pearl

Aragonite / Calcium Carbonate (CaCO3)

Pyrite Geode (Sparkling Druzy)

Iron Sulfide (FeS2) in Sedimentary Nodule

Pearl

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Amber

Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)

Sandstone (likely Arkose or Quartz Sandstone)

Arenite (SiO2 principal component)

Geode (unopened)

Chert / Chalcedony Geode (SiO2)

Graphite

Graphite (Native Carbon), Formula: C

Glauconitic Sandstone

Glauconitic Quartz Arenite

Ironstone Concretion

Siderite or Hematite Concretion

Amber

Fossilized Tree Resin (Generic formula roughly C10H16O)

Bituminous Coal (with Anthracite or Vitrinite inclusion)

Organic-rich Sedimentary Rock (Carboniferous classification)

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)

Black Jasper

Black Jasper (Silicate mineral - SiO2)

Jasper with Agate and Quartz Inclusions

Silicon Dioxide (SiO2) - Chalcedony / Quartz aggregate

Pink Opal

Amorphous Hydrous Silica (SiO2·nH2O)

Pink Opal

Hydrated Silica (SiO2·nH2O)

Chert (concretionary/nodular variant)

Microcrystalline Quartz (SiO2) with possible fossil or mineral inclusions

Petrified Wood (Silicified Wood)

Silicified fossil wood (SiO2)

Ironstone Concretion / Limonite Node

Goethite and Limonite (FeO(OH) nH2O)

Fossilized Coral

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

Chert (Yellow Jasper/Flint)

Microcrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (primarily Chalcedony or Quartz, SiO2)

Pyrite in Shaly Matrix

Iron Sulfide (FeS2)

Shale (with minor calcite veining)

Clastic sedimentary rock (primarily clay minerals and quartz)

Moss Agate

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

Petrified Wood

Silicified Wood (SiO2 - Silicon Dioxide)

Chert with Quartz Veining

Silicon Dioxide (SiO2)

Chert (with Limestone and Iron Oxide staining)

Cryptocrystalline Quartz (SiO2)

Chert (Flint Nodules)

Microcrystalline Quartz (SiO2)

Chert (Brecciated Chert)

Silicon Dioxide (SiO2)

Chert Nodule (Fossiliferous Chert)

Microcrystalline Quartz (SiO2)

Moss Agate

Chalcedony (SiO2) with inclusions of manganese or iron oxides

Petrified Wood

Silicified Wood (primarily SiO₂ / Silicon Dioxide)

Petrified Wood

Silicified Wood (SiO2)