Mineraloid (Human Made Geological Specimen)

Almandine Garnet

Almandine (Fe3Al2(SiO4)3)

Liesegang Banded Sandstone (Wonderstone)

Ferruginous Sandstone with Liesegang Rings

Sandstone Concretion

Moqui Marble / Iron-oxide Concretion (SiO2 with Hematite/Goethite)

Agate (or Chalcedony)

SiO2 (Silicon Dioxide) - a cryptocrystalline variety of quartz

Quartz

Silicon Dioxide (SiO2)

Arkosic Sandstone

Arkose (Clastic Sedimentary Rock)

Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Quartz Vein in Host Rock

Quartz (SiO2) in Mafic or Sedimentary Matrix

Sandstone (specifically Arkose or Ferruginous Sandstone)

Sandstone (SiO2 with iron oxide inclusions)

Clear Quartz (or Rock Crystal)

Quartz (SiO₂)

Aventurine (Green Aventurine)

Quartz with Fuchsite Inclusions (SiO2)

Sandstone

Arenite (primarily Quartz, SiO2)

Glauconite

(K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2

Manganese Oxide Crust on Limestone

Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Gastropod Fossil

Phylum Mollusca, Class Gastropoda (Calcium Carbonate, CaCO3)

Amygdaloidal Basalt

Basalt with secondary mineral infilling

Petrified Wood

Silicified wood (primarily SiO2)

Orthoclase Feldspar (Sunstone variety)

KAlSi3O8 (Potassium Aluminum Silicate)

Basalt with Calcite Veining

Aphanitic Mafic Igneous Rock (Basalt) with CaCO3

Native Gold Nugget

Native Gold (Au)

Porphyritic Basalt (Leopard Rock)

Porphyritic Mafic Volcanic Rock

Michigan Float Copper

Native Copper (Cu)

Moqui Marble (Shaman Stone)

Iron Oxide Concretion (Hematite/Goethite-encased Sandstone)

Milky Quartz

Silicon Dioxide (SiO2)

Granite

Granite (Felsic Plutonic Rock)

Red Sandstone (Old Red Sandstone Pebble)

Arenite with iron oxide (Fe2O3) cement

Limonite (Iron Ore/Hydrated Iron Oxide)

Limonite (mixture of FeO(OH)·nH₂O minerals, mainly Goethite, FeO(OH) and Lepidocrocite, FeO(OH))

Chert (Flint)

Chert (predominantly SiO₂ - silicon dioxide)

Almandine Garnet

Almandine (Fe3Al2(SiO4)3)

Yellow Quartz (Rough)

Silicon Dioxide (SiO2)

Ambergris (Sea Wax)

Physeter macrocephalus fecalith

Precious Coral

Corallium rubrum (Calcium carbonate with trace carotene)

Pyrite

Iron Sulfide (FeS2)

Quartz

Silicon Dioxide (SiO2)

Gold-bearing Quartz with Pyrite

Quartz (SiO2) with Gold (Au) and Pyrite (FeS2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Quartz (Milky or Cloudy variety)

Silicon Dioxide (SiO2)

Quartz (Milky/Common)

Quartz (Silicon Dioxide, SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic extrusive volcanic rock with secondary mineral infilling)