Sedimentary (Secondary Classification For A Weathered Mineral Specimen)

Vesicular basalt

Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar, pyroxene, and commonly olivine

Chert (with Limestone/Carbonate matrix)

Sedimentary cryptocrystalline silica (SiO2)

Vesicular basalt with secondary zeolite/mineral crusts

Basalt, chiefly plagioclase–pyroxene ± olivine; cavities partly filled by zeolites or calcite

Snakeskin Agate

Agate (Cryptocrystalline Quartz, SiO2)

Sandstone

Arenite

Limonite Geode (Ironstone Concretion)

Limonite [FeO(OH)·nH2O] with possible Quartz or Calcite interior

Jasper

Cryptocrystalline Quartz (SiO2)

Weathered quartz-rich metamorphic rock, likely gneiss or quartzite

Quartz–feldspar–mica metamorphic rock; exact identification is uncertain from the photograph

Copper Ore (Malachite and Azurite stained rock)

Copper-bearing rock with secondary copper carbonates

Quartz Geode or Vuggy Quartz

Silicon Dioxide (SiO2)

Chalcedony / Agate Pebble

Silicon Dioxide (SiO2)

Limonite (Iron Ore)

FeO(OH)·nH2O

Copper-bearing Quartz Vein in Host Rock

Quartz with Malachite/Chrysocolla staining

Iron-rich hematite specimen

Hematite (α-Fe₂O₃), likely with limonite/goethite and host-rock impurities

Fossiliferous limestone pebble

Calcite-rich limestone (primarily CaCO₃), with possible fossil or fossil-fragment patterns

Fossil bivalve shell

Fossilized mollusk (Bivalvia), likely an oyster or clam; exact genus requires locality and diagnostic features

Quartz (with inclusions / Sandstone fragment)

Silicon Dioxide (SiO2)

Malachite

Copper carbonate hydroxide [Cu2CO3(OH)2]

Malachite

Malachite - Cu2CO3(OH)2

Agate (Common Chalcedony)

Silicon Dioxide (SiO2)

Concretionary Sandstone

Clastic Sedimentary Rock (Sandstone with secondary mineral cementation)

Psilomelane (Black Hematite/Manganese Ore)

Barium Manganese Oxide (Formula: BaMn9O18(OH)4)

Iron-rich concretion or weathered ironstone

Limonite/goethite-rich ironstone; commonly hydrated iron oxides (FeO(OH)·nH₂O)

Quartz-veined Sandstone Pebble

Quartzite-veined Arenite

Likely weathered quartz-rich rock fragments

Uncertain; visually consistent with massive quartz or quartz-bearing sandstone

Ironstone concretion (possibly limonite/goethite-bearing)

Limonite, a mixture of hydrated iron oxides, commonly including goethite (α-FeO(OH))

Rounded fossil fragment, possibly fossiliferous limestone

Unidentified carbonate fossil or fossil-bearing limestone; exact fossil cannot be determined from the photograph

Banded Sedimentary Rock

Sedimentary Rock with Quartz/Feldspar Vein

Fossiliferous limestone

Calcite-rich limestone (primarily CaCO₃), possibly containing fossil fragments

Chalcedony Nodule / Agate

Silicon Dioxide (SiO2)

Druzy Chalcedony (Agate Geode)

Silica (SiO2) - Cryptocrystalline Quartz with druzy macrocrystalline quartz

Agate (Geode nodule fragment)

Chalcedony (cryptocrystalline variety of Quartz), SiO2

Vesicular basalt (possibly scoriaceous basalt)

Basalt, chiefly plagioclase feldspar, clinopyroxene, and iron-titanium oxides; approximate composition Mg- and Fe-rich mafic silicate rock

Chert (Arrowhead Preform or Flake)

Microcrystalline Quartz (SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Basalt River Pebble

Basalt (Mafic Extrusive Volcanic Rock)

Polished hematite (speculative)

Hematite, α-Fe₂O₃; possibly hematite-rich ironstone

Quartz (Grain/Pebble)

Silicon Dioxide (SiO2)

Sandstone (likely Arkosic or Lithic)

Clastic Sedimentary Rock (SiO2 with accessory minerals)

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)

Native Copper (Penny specimen)

Native Copper (Cu)

Quartz / Quartz Geode fragment

Silicon Dioxide (SiO2)