Rock

Weathered granite or granitic gneiss

Granitic rock, chiefly quartz, feldspar, and mica; exact identification is uncertain from the photograph

Rounded granitic pebble

Granite, likely biotite granite or granodiorite

Fossil Shell

Invertebrate fossil (Mollusca)

Ironstone Concretion (Ironstone Gourd)

Limonite/Goethite Concretion (FeOO(H))

Gneiss (Metamorphic Pebble)

Gneissic Metamorphic Rock

Druzy Quartz on Matrix

Silicon Dioxide (SiO2)

Sandstone (with Iron Staining)

Arenite (primarily SiO2 with Fe2O3/FeO(OH) oxides)

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, possibly granitic gneiss

Quartz (Druzy)

Silicon Dioxide (SiO2)

Quartzite pebble

Quartzite (mostly SiO2)

Sandstone

Arenite

Basalt

Extrusive Igneous Rock

Basalt

Mafic Igneous Rock (composed primarily of pyroxene and calcium-rich plagioclase)

Plume Agate or Moss Agate

Agate (SiO2)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Eclogite

Eclogite (High-pressure metamorphic rock)

Asphalt aggregate pavement

Bituminous asphalt concrete containing crushed stone aggregate

Granite Core Sample

Granite

Shale

Shale (Fine-grained clastic sedimentary rock)

Quartzite with Schist layers

Metamorphosed Quartz-rich Rock (Mixed Schist/Quartzite)

Milky Quartz

Silicon Dioxide (SiO2)

Dalmation Jasper

Aplite with Arfvedsonite inclusions (SiO2 with Na3(Mg,Fe2+)4AlSi8O22(OH)2)

Polished jasper or chert

Microcrystalline quartz (SiO₂), likely iron-stained jasper/chalcedony

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Serpentinite

Serpentinite (complex silicate minerals including lizardite, chrysotile, and antigorite: (Mg,Fe)3Si2O5(OH)4)

Granodiorite

Granodiorite (Intermediate intrusive igneous rock)

Red Sandstone

Sedimentary Arenite / Quartzose Sandstone

Chalcedony Geode

Silicon Dioxide (SiO2)

Basalt

Extrusive igneous rock primarily composed of plagioclase feldspar and pyroxene

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Pink Granite

Phaneritic Plutonic Igneous Rock (high K-feldspar)

Basalt

Vesicular Basalt

Red Sandstone

Sandstone (principally Quartz with Iron Oxide coating)

Granitic Pebble (Glacial Erratic)

Granite

Basalt with Vesicles

Vesicular Basalt (comprising Plagioclase Feldspar, Pyroxene, and Olivine)

Druzy Quartz Geode

Silicon Dioxide (SiO2)

Coarse-grained gray metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss (probable)

Sandstone

Arenite (primarily SiO2)

Quartz-bearing granite or pegmatitic rock

Granite, composed mainly of quartz, feldspar, and mica; exact identification is uncertain from the image

Likely weathered gneiss

Foliated metamorphic rock, commonly quartz–feldspar–mica gneiss

Sandstone

Sandstone (clastic sedimentary rock)

Dark gray-brown stone, likely basalt or fine-grained volcanic rock

Basalt (tentative; likely plagioclase–pyroxene rock)