Mineral

Sandstone (Quartzose)

Arenite (primarily SiO2)

Tumbled Moonstone

Feldspar (Orthoclase/Albite), KAlSi3O8

Sandstone

Arenite (primarily SiO2)

Turquoise

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

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Quartz Geode

Silicon Dioxide (SiO2)

Quartz Geode

Quartz (Silicon Dioxide, SiO2) in a Geode

Satin Spar (Satin Spar Selenite)

Gypsum (CaSO4·2H2O)

Satin Spar (often sold as Selenite)

Gypsum (CaSO4·2H2O)

Sandstone

Arenite (SiO2 primarily)

Red Sandstone

Arenite (Iron-rich)

Prehnite on Basalt

Prehnite - Ca2Al(AlSi3O10)(OH)2

Chrysocolla on Quartz

Chrysocolla (Cu2−xAlx(H2−xSi2O5)(OH)4·nH2O) often associated with Quartz (SiO2)

Pink Granite

Felsic Plutonic Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)

Gneiss

Gneiss (a type of metamorphic rock)

Basalt with Quartz/Calcite Veins

Extrusive mafic igneous rock with hydrothermal mineralization

Shale

Shale (comprised mostly of clay minerals and quartz)

Shark Tooth Fossil

Elasmobranchii dentition (fossilized)

Fluorite

Calcium Fluoride (CaF2)

Gneiss

Metamorphic Rock (Gneissic texture)

Greenschist

Chlorite schist (Metamorphic rock dominated by chlorite, epidote, and actinolite)

Breccia

Breccia (Clastic Sedimentary Rock)

Basalt

Basalt (Mafic volcanic rock)

Granite

Phaneritic plutonic rock (Quartz, Alkali Feldspar, and Plagioclase)

Basalt

Extrusive mafic volcanic rock

Granite

Phaneritic Igneous Rock (Granite)

Quartzite

Quartzite (primarily SiO2)

Granite (Weathered)

Phaneritic Felsic Igneous Rock

Granite

Granite (Phaneritic igneous rock consisting of Quartz, Feldspar, and Mica)

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Granite

Phaneritic Igneous Rock (Granite)

Basalt (with possible Olivine inclusions)

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Basalt

Basalt (composition predominately plagioclase feldspar and pyroxene)

Greenschist

Greenschist (Chlorite-Epidote-Actinolite Schist)

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.

Schist

Mica Schist

Geode (Unopened)

Silica Concretion / Geode (Formula: SiO2 for quartz internal contents)

Biotite Granite

Phaneritic Felsic Igneous Rock

Quartz Geode

Silicon Dioxide (SiO2) in a sedimentary host

Basalt

Basalt (Mafic volcanic rock)

Sandstone (River Cobble)

Clastic Sedimentary Rock (primarily Quartz with Feldspar)

Granite

Phaneritic Igneous Rock (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)