Sedimentary (Secondary Classification For A Weathered Mineral Specimen)

Gossan (Limonite/Ironstone)

Hydrated Iron Oxide (FeO(OH)·nH2O)

Clay (as a rock-forming material)

Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)

Granite Cobble

Granitoid (composed mainly of Quartz, Feldspar, and Mica)

Basalt Pebble

Basalt (Mafic Volcanic Rock)

Coarse Sand or Fine Gravel

Clastic Sediment (unconsolidated)

Granite (weathered pebble)

Granite (plutonic igneous rock)

Concretion or Geode (unbroken)

Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.

Milky Quartz

Silicon Dioxide (SiO2)

Chalcedony (Blue/Grey Lace Agate)

Silicon Dioxide (SiO2)

Chert (variant of Flint)

Chert (SiO2)

Jasper (likely Polychrome or Mookaite variants)

Silicon Dioxide (SiO2) with iron oxide and hydroxide inclusions

Hematite

Iron(III) oxide (Fe2O3)

Quartzite Cobble

Quartzite (principally SiO2)

Quartz (Clear to Smokey)

Silicon Dioxide (SiO2)

Orange Calcite

Calcium Carbonate (CaCO3)

Quartzite

Quartzite (SiO2)

Chondrite Meteorite

L3 Chondrite (Unequilibrated Ordinary Chondrite)

Sandstone and Quartzite Specimens

SiO2 with varying mineral/clastic inclusions

Porphyritic Basalt Pebble

Basalt with plagioclase phenocrysts

Breciated Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Vesicular Basalt (or Scoria)

Vesicular Basalt

Pink Dyed Agate

Silicon Dioxide (SiO2) with synthetic pigment

Red Sandstone

Arenite (Ferruginous Sandstone)

Ironstone (likely Limonite or Goethite)

Ferruginous sedimentary rock (FeO(OH)·nH2O)

Turquoise

Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

Sandstone

Arenite (primarily SiO2)

Ferruginous Sandstone (Ironstone Nodules)

Ferruginous Sandstone with Limonite/Goethite coating (Fe2O3·H2O)

Bauxite

Bauxite (Al(OH)3, AlO(OH))

Fossiliferous Limestone

Calcium Carbonate (CaCO3)

Brecciated Chert

Sedimentary Chert (SiO2) with Calc-Silicate mineralization

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Septarian Nodule (Micro-fragment)

Septarian Nodule / Concretion (CaCO3 + CaMg(CO3)2 + Quartz)

Porphyry

Porphyritic Andesite/Basalt

K2 Stone (or K2 Jasper)

Azurite-in-Granite (Potassium Feldspar, Quartz, Plagioclase, Muscovite, and Azurite)

Limonite (Iron Stone/Gossen)

Limonite (FeO(OH)·nH2O)

Sandstone (Ferruginous)

Arenite (Fe-rich SiO2)

Prehnite

Prehnite Ca2Al2Si3O10(OH)2

Gold Nugget

Native Gold (Au)

Magnetite (likely with weathered Limonite/Hematite)

Magnetite (Fe3O4) with iron oxide weathering

Gray Quartzite Pebble

Quartzite (chemically SiO2)

Magnetite Sand (Black Sand)

Magnetite (Fe3O4)

Olivine-rich Basalt with Peridotite Xenoliths

Porphyritic Basalt containing Dunite/Peridotite (Mg,Fe)2SiO4