Mineral Side Rock

Coarse-grained gray metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss (probable)

Druzy Quartz on Limestone

Silicon Dioxide (SiO2) on Calcium Carbonate (CaCO3)

Greenstone (likely altered mafic rock)

Chlorite- and amphibole-bearing metabasalt; exact identification requires testing

Coarse sand with a small pebble

Unconsolidated siliciclastic sediment, chiefly quartz and rock fragments

Basalt with Quartz Vein

Extrusive Igneous Rock / Volcanic Rock

River Rock

Sedimentary clast

Sandstone (with Rock Art)

Sandstone (Clastic Sedimentary Rock)

Sandstone (Wonderstone)

Clastic Sedimentary Rock (primarily SiO2)

Sandstone

Sedimentary rock composed mainly of sand-sized minerals or rock grains

Mixed rock and mineral collection

Unidentified assortment of geological specimens; individual species cannot be determined from the image

Likely tumbled greenstone (identity uncertain)

Greenstone: metamorphosed mafic volcanic rock, commonly composed of chlorite, actinolite, and epidote

Vesicular Basalt

Vesicular Basalt

Sandstone

Clastic Sedimentary Rock

Druzy quartz on matrix

Quartz (SiO₂), likely microcrystalline-to-fine crystalline drusy quartz

Sandstone or possibly a conglomerate

Arenite (if sandstone)

Red Sandstone

Sandstone (principally Quartz with Iron Oxide coating)

Crushed Granite and Basalt

Phaneritic Igneous Rock / Aphanitic Igneous Rock

Pebble (likely Sandstone or Granitic Pebble)

Clastic Sediment (or specific rock type, e.g., Arenite, Granitoid Pebble)

Quartz-rich geode or mineralized cavity in host rock

Likely a quartz-bearing geode; the pale crystals may be quartz (SiO₂), but the photo is not detailed enough for a firm identification.

Quartz with Sericite and Cinnabar

Silicon Dioxide (SiO2) with muscovite/sericite and mercury sulfide (HgS)

Geode

Quartz nodule / Chalcedony-lined cavity

Vesicular Basalt / Scoria pebble

Extrusive igneous rock with amygdaloidal infilling

River Rock / Stream Pebble

Fluvial Clast / Rounded Sedimentary Particle

Weathered, rounded rock (likely metamorphic or igneous)

Undetermined; possibly a quartz- and feldspar-bearing rock

Unidentified gray mineral/rock fragment

Indeterminate from the photograph; possibly a quartz- or feldspar-bearing rock fragment

Sandstone (with Iron Staining)

Clastic sedimentary rock (SiO2 with Fe2O3 oxides)

Greenstone (likely chlorite- or epidote-rich metamorphic rock)

Greenstone; commonly metamorphosed basalt or dolerite, with chlorite, epidote, and actinolite

Sandstone with Quartz Vein

Arenite with Crystalline Silica (SiO2)

Likely serpentinite (green serpentine rock)

Serpentinite, composed chiefly of serpentine-group minerals (antigorite, lizardite, and/or chrysotile)

Fluorite

Calcium Fluoride (CaF2)

Polished dark-speckled igneous pebble, likely diorite or gabbro

Probable diorite (plagioclase feldspar and hornblende/biotite); exact identification is uncertain from the image

Not a geological specimen

N/A (man-made object)

Likely weathered granite or granitic gneiss

Granite: quartz + feldspar + mica; possibly gneiss if the faint texture reflects foliation

Shale

Shale (Lutite)

Shale

Argillaceous Rock

Agate Geode

Silicon Dioxide (SiO2) - Chalcedony variety

Sandstone (Micaceous)

Clastic Sedimentary Rock (primarily SiO2 with Mica)

Sandstone

Arenite

Sandstone

Arenite

Sandstone (Ferruginous)

Arenite (Siliclastic Sedimentary Rock)

Quartz vein in host rock

Milky quartz (SiO₂) with likely metamorphic country rock, possibly gneiss or schist

Desert Rose (Baryte or Selenite variant)

Barium Sulfate (BaSO4) or Gypsum (CaSO4·2H2O) with Sand inclusions