This Is Not A Rock Or Mineral

Druzy Quartz on Chalcedony Matrix

Silicon Dioxide (SiO2)

Halite

Sodium Chloride (NaCl)

Sandstone or Quartzite pebble

Sandstone (Quartz arenite) or Quartzite

Greywacke (likely)

Greywacke (a type of sandstone)

Sandstone (Ferruginous)

Sandstone (primarily SiO2 with iron oxide Fe2O3 staining)

Tumbled pink granite

Granite (quartz, feldspar, and mica; exact variety uncertain)

Serpentine Sphere

Serpentinite

Fossilized Bark

Lepidodendron / Sigillaria fossil impression

Speckled feldspar-rich pebble

Likely leucocratic granite or granitic pegmatite, chiefly potassium feldspar with dark biotite or amphibole

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase ± pyroxene/olivine)

Sandstone

Sandstone (composed predominantly of Quartz, SiO2)

Quartz–iron-oxide breccia or weathered quartz-bearing rock

Quartz (SiO₂) with limonite/goethite and possibly iron sulfides in a brecciated host

Granite

Intrusive Igneous Rock

Small dark mineral or rock fragment

Undetermined; possibly a dark mafic mineral such as biotite or magnetite

Weathered golden-brown mineral/rock fragment

Indeterminate from image; possibly iron-stained quartz, feldspar, or a sulfide-bearing rock

Unidentified brown mineral/rock fragment

Indeterminate from image; possibly iron-stained quartz, feldspar, or weathered limonite

Sandstone Cobble with Iron Staining

Arenite with Limonite/Hematite staining

Coarse sand with a small pebble

Unconsolidated siliciclastic sediment, chiefly quartz and rock fragments

Sandstone

Clastic sedimentary rock (Quartz arenite or arkose)

Quartz with Schist Inclusion

Crystalline Silicon Dioxide (SiO2) with Muscovite/Biotite Schist

Sandstone (lithic wacke)

Arenite / Lithic Wacke (mostly SiO2 with rock fragments)

Sandstone (likely Greywacke or Lithic Sandstone)

Arenite / Wacke

Fossil Snail

Gastropoda fossil

Quartz-veined Metamorphic Rock

Quartz-veined Schist or Gneiss

Polished moss agate (likely)

Chalcedony, microcrystalline SiO₂, with included green minerals such as chlorite or hornblende

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)

Smooth river pebble

Indeterminate lithology; likely fine-grained quartz-rich sandstone, siltstone, or weathered chert

Druzy Quartz Geode

Silicon Dioxide (SiO2)

Gravel and Pebbles

Unconsolidated rock fragments / detrital sediment

Sea stacks and coastal cliffs

Likely basaltic sea stacks (rock type cannot be confirmed from the image)

Granite

Intrusive Igneous Rock

Mixed mineral and rock specimens

Unidentified assortment; visible pieces may include rose quartz, green aventurine, quartz, and a gray crystalline rock, but the image is insufficient for exact identification.

Asphalt Pavement (with aggregate)

Asphalt concrete

Pink granite (likely weathered granite)

Granite, composed mainly of quartz, feldspar, and mica

Red heart-shaped glass bead in a wire-wrapped jewelry charm

Likely colored glass (amorphous silica-based material); the image does not show an identifiable geological specimen

Quartz Geode

Silicon Dioxide (SiO2)

Granite or Porphyritic Igneous Rock (weathered)

Granitoid

Quartz Vein in Sedimentary Rock

Silicon Dioxide (SiO2) with host Chert or Limestone

Likely garnet-bearing rock

Garnet in a dark metamorphic matrix; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃

Sandstone

Arenite

Sandstone

Arenite (predominantly SiO2 quartz grains)

Sandstone (Quartzose)

Arenite (primarily SiO2)