Mineral, Possibly Rock Fragment Containing A Mineral

Quartz / Common Agate

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Granite Pebble

Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)

Sandstone (likely Calcareous or Quartz-rich)

Arenite (SiO2 based typically)

Common Pebble / Sedimentary Rock Fragment

Lithified clastic sediment

Quartz-rich pegmatite (possibly quartz–feldspar rock)

Granite pegmatite; chiefly quartz (SiO₂) with feldspar and minor mica/iron staining

Amygdaloidal Rhyolite

Amygdaloidal felsic extrusive rock

Red Sandstone

Arenite (primarily composed of SiO2 with Fe2O3 cement)

Tumbled pale greenish stone, likely serpentine or altered limestone

Probable serpentine-group rock (antigorite/lizardite), possibly serpentinite; identification is visual only

Quartz Druzy (on Matrix)

Silicon Dioxide (SiO2)

Sandstone (lithic wake or graywacke)

Clastic sedimentary rock (primarily quartz and lithic fragments)

Man-made Synthetic Material (Plastic/Composite)

Acrylonitrile Butadiene Styrene (ABS) or High-Impact Polystyrene (HIPS)

Granite

Felsic intrusive igneous rock

Dalmatian Jasper

Peralkaline Quartz-Feldspar Rock with Arfvedsonite

Mixed river stones and gravel

Polymictic alluvial clasts; individual pieces may include quartzite, granite, basalt, sandstone, limestone, and slate

Weathered basalt or iron-rich volcanic rock

Mafic volcanic rock, likely basalt; exact identification requires testing

Sandstone

Arenite (primarily Quartz-rich sedimentary rock)

Quartz Geode

Silicon Dioxide (SiO2)

Fossiliferous Shale

Fossiliferous Mudstone / Shale

Iron-stained quartz vein fragment

Quartz (SiO₂), likely with limonite/goethite iron oxides and minor sulfides

Granite

Intrusive igneous felsic rock

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Lapis Lazuli

Lapis Lazuli (Primary mineral: Lazurite (Na,Ca)8(AlSiO4)6(SO4,S,Cl)2)

Garnetiferous Pegmatite

Pegmatite with Almandine Garnet and Muscovite

Lazulite Quartzite

Quartzite with Lazulite (SiO2 with (Mg,Fe)Al2(PO4)2(OH)2)

Weathered quartz-rich rock fragment

Likely quartz-bearing feldspathic rock; exact identification requires testing

Shungite (or Black Onyx / Obsidian)

Amorphous Carbon (Shungite) / SiO2 (Onyx/Obsidian)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Granite fragment

Granite (Felsic intrusive igneous rock)

Weathered mafic rock (probable basalt or gabbro fragment)

Basalt–gabbroic rock; chiefly plagioclase feldspar and pyroxene, possibly olivine

River Pebble

Quartzo-feldspathic rock fragment

Vesicular basalt (probable)

Basalt; chiefly plagioclase feldspar, clinopyroxene, and iron-rich minerals, with vesicles possibly lined by zeolites or calcite

Breccia

Breccia (Clastic sedimentary rock)

Quartz-bearing rock fragment

Likely quartz (SiO₂) with iron-oxide staining and possible host-rock grains

Sandstone

Arenite (composed primarily of SiO2, or Silicon Dioxide)

Sandstone

Arenite (primarily SiO2)

Granite

Felsic intrusive igneous rock

Schist

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

Quartz Druse on Basalt Matrix

Silicon Dioxide (SiO2)

Ferruginous Sandstone (Ironstone)

Clastic sedimentary rock (SiO2 with Fe2O3/FeO(OH) cement)

Smoky Quartz

Silicon Dioxide (SiO2)

Not a geological specimen

N/A (man-made object)