Man Made Material, Not A Natural Rock Or Mineral Specimen

Sandstone (Ferruginous)

Arenite (with Iron Oxides)

Blue Banded Agate (Dyed)

Silicon Dioxide (SiO2) - Variety of Chalcedony

Rough amber-like brown mineral specimen

Uncertain from photograph; possibly iron-stained quartz, common opal, or resinous amber

Turquoise

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

Sandstone (Quartzite-rich)

Clastic Sedimentary Rock (primarily SiO2)

Likely basalt with a pale mineral-filled vesicle

Vesicular basalt, probably containing calcite or zeolite (uncertain from image)

Magnetite (Lodestone)

Iron(II,III) oxide (Fe3O4)

Limonite with Quartz

Hydrated Iron Oxide Hydroxide, FeO(OH)·nH₂O with SiO₂

Dyed Blue Agate

Silicon Dioxide (SiO2)

Granite / Gneiss (Coarse-Grained Felsic Rock)

Granite (Quartz-Feldspar-Mica aggregate)

Sandstone

Sandstone (lithified arenite/wacke)

Sandstone (likely Arkosic or Quartzose)

Sandstone (SiO2 with inclusions)

Unidentified weathered rock, possibly quartz-bearing granite or rhyolite

Indeterminate; likely quartz–feldspar-rich silicate rock

Granite Pebble

Felsic intrusive igneous rock

Quartz-rich metamorphic rock, likely mica schist

Mica schist; chiefly quartz (SiO₂) with biotite/muscovite mica and possible feldspar

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Granodiorite with Quartz Veining

Granodiorite (containing Plagioclase Feldspar, Quartz, and Biotite/Hornblende) with Quartz (SiO2) veins

Chalcedony (Agate / Jasper Specimen)

Silicon Dioxide (SiO2)

Tumbled dark stone, likely basalt or basaltic rock

Fine-grained mafic volcanic rock; commonly basalt, composed chiefly of plagioclase and pyroxene with possible olivine and iron oxides

Fossilized oyster shell

Bivalvia; likely an oyster (Ostreidae), partly mineralized with calcite

Pink agate (likely dyed or coated)

Microcrystalline quartz, SiO₂ (chalcedony/agate)

Quartz-rich granite or pegmatitic rock

Granite/pegmatite; chiefly quartz (SiO₂), feldspar, and minor mica

Chert (Jasper variety) with Iron Oxide staining

Cryptocrystalline Quartz (SiO2) with Goethite/Limonite impurities

Granite (Pebble)

Granite (composed of Quartz, Feldspar, and Mica/Amphibole)

Quartz-rich rock fragment

Microcrystalline quartz (SiO₂), possibly chalcedony or quartz-bearing breccia

Shale (with minor calcite veining)

Clastic sedimentary rock (primarily clay minerals and quartz)

Shale with Coprolite influence

Argillaceous sedimentary rock (Shale/Mudstone)

Tektite (Indochinite)

Tektite (Natural silica glass)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Blue Banded Agate (Dyed)

Silicon Dioxide (SiO2) - variety of Chalcedony

Green aventurine beads

Quartz (SiO₂), typically green quartzite/aventurine with fuchsite mica inclusions

Sandstone (Banded)

Arenite

Gabbro

Gabbro

Sandstone

Clastic Sedimentary Rock (composed mostly of quartz and/or feldspar)

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase + pyroxene, sometimes olivine)

Sandstone

Arenite

Shale

Fissile Mudrock (Clay-rich Sedimentary Rock)

Likely yellow chalcedony or citrine cabochon

Cryptocrystalline quartz (chalcedony), SiO₂; alternatively quartz variety citrine

Conglomerate

Clastic sedimentary rock (Conglomerate)

Likely weathered basalt or dark volcanic rock

Basalt; primarily plagioclase feldspar and pyroxene, with possible olivine and iron oxides

Pearl (Biogenic)

Nacre / Calcium Carbonate (CaCO3)