Sedimentary (Secondary Mineral Formation)

Limestone Pebble

Calcium Carbonate (CaCO3)

Red Chert

Microcrystalline Quartz (SiO2)

Red Sandstone

Clastic sedimentary rock (primarily SiO2 with Fe2O3 iron oxide staining)

Vesicular Basalt with Secondary Mineral Infill

Mafic Volcanic Rock (Basalt)

Azurite with Malachite

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

Spondylus Oyster Calcification / Fossilized Oyster

Spondylus (Thorny Oyster) / Calcium Carbonate (CaCO3)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Yellow Diamond (Faceted)

Diamond (C - Pure Carbon)

Red Sandstone (Arkose)

Clastic Sedimentary Rock (Lithic Arkose)

Sandstone (Yellow/Tan Sandstone)

Arenite (primarily Quartz, SiO2)

Malachite Coating on Host Rock

Malachite [Cu2CO3(OH)2]

Chert (specifically a stream-worn Chert Nodule)

Sedimentary Cryptocrystalline Quartz (SiO2)

Agate Slices and Clear Quartz Points

Agate (SiO2 Chalcedony) and Clear Quartz (SiO2 Crystalline)

Red Sandstone

Arenite (primarily Quartz, SiO2, with Iron Oxide/Hematite)

Clear Quartz

Silicon Dioxide (SiO2)

Hematite (Tumbled)

Iron(III) oxide (Fe2O3)

Quartz with Limonite Staining

Silicon Dioxide (SiO2) with Hydrated Iron Oxide (FeO(OH)·nH2O)

Red Sandstone Pebble

Arenite (primarily Quartz SiO2 with Hematite Fe2O3 staining)

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(OH)2

Specular Hematite with Pyrite

Iron Oxide (Fe2O3) with Iron Sulfide (FeS2)

Quartz

Silicon Dioxide (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Red Jasper

Silicon dioxide (SiO2) with iron oxide inclusions

Hematite

Iron(III) oxide (Fe2O3)

Greywacke (Briarcliff Schist/Gneiss)

Manhattan Schist / Fordham Gneiss complex

Magnetite

Magnetite (Fe3O4)

Red Sandstone

Arenite with Hematite (Fe2O3) cement

Amethyst Geode

Quartz (SiO₂) with iron impurities

Sandstone (Red)

Arenite (primarily SiO2 with Iron Oxide staining)

Banded Iron Formation (BIF) / Tiger Iron variety

Banded Iron Formation (predominantly Hematite, Magnetite, and Chert/Quartz - SiO2 + Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Banded Jasper with Hematite or Quartz

Silicon Dioxide (SiO2) with impurities

Pearl (as a Biogenic Mineral)

Calcium Carbonate (mostly Aragonite) with Conchiolin; CaCO3

Limestone

Calcium Carbonate (CaCO3)

Banded Chert

Silicon Dioxide (SiO2)

Tiger Iron / Banded Iron Formation

Banded Iron Formation (SiO2 with Fe2O3 and FeOOH)

Magnetite

Magnetite (Fe3O4)

Chert (Banded)

Microcrystalline Quartz (SiO2)

Ironstone Concretion (Siderite Nodules)

Siderite (FeCO3) in Mudstone or Sandstone matrix

Sandstone

Arenite (composed primarily of SiO2)

Dyed Pink Agate Slice

Cryptocrystalline variety of Quartz (SiO2)