Non Geological

Devil's Toenail (Fossil Oyster)

Gryphaea arcuata (Calcium Carbonate, CaCO3)

Petrified Wood

Silicified Wood (SiO2)

Brachiopod Fossil in Chert

Phylum Brachiopoda within Microcrystalline Quartz (SiO2)

Ferruginous Siltstone or Mudstone

Ferruginous Siltstone / Goethitic Sandstone

Shatter Cone

Impactite (Shatter Cone texture)

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)

Limonite and Goethite encrusted Chert/Ironstone

Hydrated Iron Oxide (FeO(OH)·nH2O) with cryptocrystalline Silica (SiO2)

Peridotite (with Olivine)

Peridotite (rich in Olivine, (Mg,Fe)2SiO4)

Ammonite Fossil (Polished Section)

Ammonoidea (typically mineralized with Calcite CaCO3)

Ironstone Concretion (Limonite/Goethite)

Ferruginous Sandstone or Limonite (FeO(OH)·nH2O)

Quartzite with Chert inclusions

Metamorphosed Quartz-rich Rock (SiO2)

Ironstone Concretion / Limonite

Goethite and Limonite (FeO(OH)·nH2O)

Quartz (likely)

Quartz (SiO2 - Silicon Dioxide)

Aragonite (specifically Mexican Marbled Onyx)

Aragonite (Calcium Carbonate, CaCO3)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)

Glauconitic Sandstone (Greensand)

Glauconitic Quartz Arenite (Formula: (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Sandstone (Quartzose)

Arenite (SiO2 based)

Ferruginous Quartzite (also known as Ironstone or Gossan)

Ferruginous Quartzite with Goethite/Hematite staining

Scoria

Vesicular Basalt / Scoriaceous Basalt

Scoria (Lava Rock)

Mafic extrusive volcanic rock (Scientific formula varies based on mineral content: primarily SiO2, MgO, and FeO)

Azurite Geode

Azurite (Cu3(CO3)2(OH)2)

Grey Banded Agate

Chalcedony (Silicon Dioxide, SiO2)

Chert (varieties: Flint or Chalcedony)

Microcrystalline Quartz (SiO2)

Wishing Stone with Quartz Vein

Hydrothermal Quartz Vein in Metasedimentary Matrix (primarily SiO2)

Acicular Azurite (indicated by deep blue, fibrous/fuzzy appearance)

Azurite (Copper Carbonate Hydroxide) - Cu3(CO3)2(OH)2

Quartz (Iron-stained or Ferruginous)

Silicon Dioxide (SiO2)

Basalt with Calcite Veins

Basalt (Mafic Volcanic Rock)

Banded Iron Formation (Jaspillite)

Banded Iron Formation (BIF) / Jaspillite

Azurite and Malachite on Matrix

Cu3(CO3)2(OH)2 (Azurite) and Cu2CO3(OH)2 (Malachite)

Chrysocolla and Azurite in Matrix

Hydrated copper phyllosilicate (Chrysocolla - Cu2H2Si2O5(OH)4) and Copper carbonate (Azurite - Cu3(CO3)2(OH)2)

Chert (Septarian or Nodular variety)

Microcrystalline Quartz (SiO2)

Ferruginous Sandstone

Clastic sedimentary rock (primarily Quartz with Iron Oxide cement)

Chlorite Phantom Quartz

Silicon Dioxide (SiO2) with Chlorite group inclusions [(Mg,Fe)3(Si,Al)4O10(OH)2·(Mg,Fe)3(OH)6]

Rhyolite

Rhyolite (High-silica volcanic rock)

Turritella (Gastropod Fossil)

Turritella (Genus of gastropods), CaCO3 (Calcium Carbonate or Silicified Agate)

Chalk

Calcium Carbonate (CaCO3)

Basalt with Quartz/Quartzite Veins

Aphanitic Mafic Volcanic Rock with Siliceous Infillings

Sandstone

Clastic sedimentary rock (primarily SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz Pebble

Quartz (Silicon Dioxide - SiO2)

Azurite-Malachite with Limonite

Cu3(CO3)2(OH)2 (Azurite) / Cu2CO3(OH)2 (Malachite)