Synthetic (Not A Rock Or Mineral)

Granite

Phaneritic Plutonic Igneous Rock (primarily composed of quartz, alkali feldspar, and plagioclase)

Schist

Mica Schist (primarily consisting of muscovite KAl2(AlSi3O10)(OH)2 or biotite K(Mg,Fe)3(AlSi3O10)(OH)2)

Turquoise

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

Sandstone

Arenite (SiO2 primarily)

Glauconite (Glauconitic Sandstone)

Glauconite [(K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2]

Sandstone (with possibly iron oxides and other minerals)

Sandstone

Sandstone

Sandstone (various mineral compositions)

Amethyst

Amethyst (Silicon Dioxide - SiO2)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Quartzite River Rock

Quartzite (primarily SiO2)

Shale

Clastic sedimentary rock (primarily clay and silt minerals)

Granodiorite

Granodiorite (Intermediate intrusive igneous rock)

Concretion

Various mineral compositions, typically carbonate or iron oxide cemented sediment

Quartz Geode

Silicon Dioxide (SiO2)

Gneiss

High-grade regional metamorphic rock (Foliated)

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic Volcanic Rock)

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals, Mg3Si2O5(OH)4)

Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Agate

Agate (Silicon Dioxide, SiO2)

Quartz (Druzy)

Silicon Dioxide (SiO2)

Sandstone (Banded)

Clastic sedimentary rock (primarily SiO2)

Veined Pebble (likely a Quartz-Veined Pebble)

Pebble with Mineral Vein (e.g., Quartz Vein in a Chert/Mudstone Pebble)

Sandstone (Banded)

Clastic Sedimentary Rock (primarily SiO2)

Unidentified Rock Fragment

Unknown

Sandstone (likely Arkosic or Lithic)

Clastic Sedimentary Rock (SiO2 with accessory minerals)

Gold-bearing Quartz with Iron Oxides

Quartz (SiO2) with Limonite/Goethite (FeO(OH)) and Pyrite (FeS2)

Garnet Schist

Almandine Garnet Schist (Fe3Al2(SiO4)3 in Schistose matrix)

Garnet Schist

Almandine-Muscovite Schist

Fluorite with Quartz coating

Calcium Fluoride (CaF2) with Silicon Dioxide (SiO2)

Amygdaloidal Basalt with Epidote/Chlorite

Basalt (containing (Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH)))

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic Extrusive volcanic rock)

Amygdaloidal Basalt

Amygdaloidal Basalt (with secondary mineral infilling)

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 based)

Sandstone

Arenite (primarily SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Amygdaloidal Basalt

Amygdaloidal Mafic Volcanic Rock

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Milky Quartz

Silicon Dioxide (SiO2)

Ironstone Concretion (Ironstone Gourd)

Limonite/Goethite Concretion (FeOO(H))

Banded Gneiss

Gneiss (Metamorphic Rock)

Quartz (Druzy)

Silicon Dioxide (SiO2)

Calcite (Yellow/Orange variety - sometimes called Honey Calcite)

Calcite