Rock

White Marble

Recrystallized Calcite (CaCO3)

Serpentinite

Serpentinite (composed primarily of minerals in the Serpentine group)

Banded Gneiss

Gneiss (High-grade metamorphic rock)

Sandstone (Greywacke)

Arenite / Wacke (Mainly SiO2 with various lithic fragments)

Basalt with Quartz/Calcite Vein

Amygdaloidal Basalt (matrix) with Mineral Vein filling

Sandstone or Limestone

Arenite or Calcareous Sedimentary Rock

Sandstone

Arenite (SiO2 predominantly)

Mexican Crazy Lace Agate

Silicon Dioxide (SiO2) with iron and aluminum inclusions

Sandstone

Arenite (SiO2 based with various mineral cements)

Quartz Crystal (specifically a Double-Terminated variety)

Silicon Dioxide (SiO2) - Low Quartz

Amphibolite

Amphibolite

Quartz in Host Rock

Silicon Dioxide (SiO2) in Rhyolite or Granite matrix

Thunderegg (Ate Agate/Jasper Geode)

Silicon Dioxide (SiO2) within Rhyolite/Perlite matrix

Sandstone (Quartz-rich)

Arenite (primarily SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Vesicular Basalt (River Rock)

Afanitic Vesicular Basalt

Sandstone (Ferruginous)

Clastic Sedimentary Rock (SiO2 with FeO/Fe2O3)

Gold in Quartz Matrix

Native Gold (Au) with Quartz (SiO2) and Slate/Shale

Biotite Schist

Biotite Schist (Rich in K(Mg,Fe)3AlSi3O10(OH)2)

Gneiss

High-grade Metamorphic Gneiss

Banded Sandstone (Liesegang Rings)

Sedimentary Arenite (SiO2 with FeO/Fe2O3 impurities)

K2 Jasper (Beads)

Granodiorite with Azurite and Malachite

Shale (sub-type: Carbonaceous Shale)

Lutaceous Sedimentary Rock

Painted River Rock

Anthropogenic-modified Siliciclastic Sedimentary Rock

Basalt

Mafic extrusive volcanic rock (composed primarily of Plagioclase feldspar and Pyroxene)

Unakite

Epidotized Granite (Composed of Orthoclase Feldspar, Epidote, and Quartz)

Andesite Porphyry

Andesite (extrusive volcanic rock)

Crushed Limestone

Calcium Carbonate (CaCO3)

Turquoise

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

Sandstone or Siltstone

Arenite (if sandstone)

Banded Sandstone

Arenite with Liesegang banding

Agate Geode Slice (with Druzy Quartz)

Silicon Dioxide (SiO2)

Druzy Quartz on Limestone

Silicon Dioxide (SiO2)

Chert (Quartzite-rich River Pebble)

Silicon Dioxide (SiO2)

Granite (Specimen: Logan Rock)

Phaneritic plutonic igneous rock (mainly Quartz, Feldspar, and Mica)

Quartz Vein in Host Rock (Pebble)

Quartz (SiO2) with sandstone or siltstone matrix

Common Opal in Host Rock

Hydrated Silica (SiO2·nH2O)

Granite (Background) and Quartzite/River Pebble (Foreground Heart)

Phaneritic Felsic Igneous Rock (Granite background)

Greenschist

Greenschist (chlorite-epidote schist)

Scoria

Extrusive Basaltic Scoria

River Rock (Basalt)

Aphanitic Basaltic Rock

Unakite

Epidote-Feldspar rock