Not A Rock (Synthetic Material)

Rounded gray river pebble, likely fine-grained basalt or andesite

Basaltic-andesitic volcanic rock; commonly plagioclase feldspar, pyroxene, and minor iron oxides

Iron-stained quartz-rich rock, possibly quartzite or silicified breccia

Quartz (SiO₂)-dominant rock with iron-oxide minerals, chiefly hematite/goethite

Unidentified rock fragments

Indeterminate; likely a weathered, iron-stained silicate rock

Sandstone

Clastic Sedimentary Rock

Sandstone

Sedimentary Clastic Rock

Sandstone

Clastic Sedimentary Rock

Sandstone

Clastic sedimentary rock

Sandstone

Clastic Sedimentary Rock

Slate

Metamorphic Pelitic Rock

Jasper

Microcrystalline Quartz (Chalcedony), SiO2

Weathered granite or granitic gneiss

Granite; predominantly quartz, feldspar, and mica (exact identification is uncertain from the image)

Coal

Combustible sedimentary rock

Tumbled amber-colored agate or chalcedony

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

Serpentinite with green serpentine inclusion

Serpentinite; serpentine-group minerals, chiefly antigorite, lizardite, or chrysotile, with possible magnetite

Sandstone (Banded)

Clastic Sedimentary Rock: Arenite

Sandstone (Iron-stained)

Arenite with Limonite/Hematite staining

Diamond (Cut Specimen)

Diamond (pure carbon, C)

Greenstone / altered basalt fragment

Likely chlorite–epidote–actinolite altered basalt; exact identification requires testing

Gravel and Sand Aggregate

Unconsolidated Clastic Sediment

Sedimentary Breccia

Breccia (Clastic Sedimentary Rock)

Sandstone (Garden Boulder)

Sandstone (SiO2 dominated)

Painted Pet Rock (Quartzite/Sandstone base)

Silicon Dioxide (SiO2) with anthropomorphic acrylic embellishments

Quartzite

Quartzite (SiO2)

Serpentine

Hydrous magnesium iron silicate, (Mg,Fe)3Si2O5(OH)4

Botryoidal chalcedony geode

Microcrystalline quartz (SiO₂), likely chalcedony with quartz druse

Tumbled quartz-rich pebble

Quartz (SiO₂), likely a rounded quartzite or quartz-rich sandstone pebble

Weathered quartz-rich rock fragment

Indeterminate; likely quartz-bearing granitoid or quartzite

Sandstone

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (SiO2 based)

Breciated Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Sandstone Pebble

Sandstone (primarily Quartz, SiO2)

Sandstone

Arenite (primarily SiO2)

Weathered porphyritic volcanic rock (likely basaltic andesite)

Porphyritic basaltic andesite; mineral assemblage likely plagioclase, pyroxene, and iron oxides

Weathered brown rock fragment, possibly iron-rich sandstone or altered basalt

Indeterminate; likely an iron-oxide–stained silicate rock

Weathered mica-rich schist

Muscovite–biotite schist, possibly quartz-bearing

Sandstone

Arenite (SiO2 based)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Gray Granite

Granite (Phaneritic igneous rock)

Pumice

Pumice (Volcanic Rock)