Organic Materia (Not A Rock Or Mineral)

Moss Agate

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

Turquoise and Red Coral

Turquoise: CuAl6(PO4)4(OH)8·4H2O; Red Coral: Corallium rubrum (organic gemstone)

Dendritic Agate

Chalcedony (SiO2) with manganese/iron oxide inclusions

Chert (Jasper-like Silicate)

Microcrystalline Quartz (SiO2)

Chert with Quartz/Calcite Vein

Microcrystalline Silica (SiO2)

Amber

Succinite (formula varies, primarily C10H16O)

Sandstone (Red / Iron-stained)

Sandstone (composed predominantly of SiO2 with Fe2O3 cement)

Tumbled brown chalcedony or quartzite pebble

Microcrystalline quartz (SiO₂), likely chalcedony; exact identification requires testing

Sandstone (Weathered Coastal Boulder)

Arenite (composed primarily of SiO2)

Petrified Wood

Silicified Wood (primarily SiO₂ / Silicon Dioxide)

Chert Concretion

Microcrystalline Quartz (SiO2)

Red coral cabochon (likely dyed or reconstructed coral)

Corallium rubrum or other calcareous coral; chiefly aragonite (CaCO₃)

Yellow Chert (Jasper)

Silicon Dioxide (SiO2)

Precious Coral (Red Coral)

Corallium rubrum (Calcium Carbonate, CaCO3)

Chert (Septarian or Nodular variety)

Microcrystalline Quartz (SiO2)

Fossilized Coral

Rugosa / Scleractinia (Agatized or Calcitized Coral)

Fossilized Horn Coral

Order Rugosa (Rugose Coral)

Fossilized Coral (Petrified Coral)

Lithostrotionella (example genus) / Scleractinia

Chert with Iron Oxide Staining

Microcrystalline Quartz (SiO2) with Limonite/Goethite staining

Ironstone Concretion / Goethite-Hematite Geode

Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)

Fossilized Coral

Cnidaria fossil / Calcite-replaced coral

Chert Pebble

Microcrystalline Quartz (SiO2)

River-worn Chert

Microcrystalline Quartz (SiO2)

Tumbled yellow jasper or silicified rock fragment

Microcrystalline quartz (chalcedony), SiO₂, likely iron-oxide colored

Chert (with Quartz Vein)

Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)

Fossiliferous Limestone containing a Brachiopod or Mollusk Impression

Biogenic Sedimentary Rock / Fossiliferous Limestone

Blue Agate (Tumbled and Dyed)

Silicon Dioxide (SiO2) with likely organic dyes

Tumbled brown agate (likely moss or plume agate)

Microcrystalline quartz, chiefly chalcedony (SiO₂), with iron-oxide and possibly mineral inclusions

Petrified Wood

Silicon Dioxide (SiO2)

Limestone with Quartz/Calcite Veins

Sedimentary Limestone (CaCO3 with SiO2 or CaCO3 intrusions)

Fossiliferous Sandstone / Fossil Fragment

Fossiliferous Sedimentary Matrix with Indeterminate Fossil Material

Ironstone Concretion

Siderite / Hematite-bearing Sedimentary Rock

Pink Opal

Amorphous Hydrous Silica (SiO2·nH2O)

Chert (Common Opal/Agatized Rock)

Microcrystalline Quartz (SiO2) with potential Chalcedony/Opaline silica

Brachiopod Fossil in Limestone

Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)

Ironstone Concretion (Boxwork)

Siderite-Limonite Concretion (FeO(OH)·nH2O)

Fossilized Shark Tooth

Chondrichthyes tooth

Banded Chert (likely Flint or Jasper variety)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified wood (primarily Silicon Dioxide, SiO2)

Shale (possibly Carbonaceous or Oil Shale)

Laminated Mudstone (primarily clay minerals and quartz)

Banded Chert / Sandstone Pebble

Microcrystalline Quartz (SiO2) / Silicified Sandstone

Travertine (Tufa)

Chemical Limestone (CaCO3)