Rock (Likely Sedimentary)

Druzy quartz geode

Microcrystalline quartz (SiO₂), commonly lining a volcanic geode cavity

Granite River Pebble

Granite (composed of Quartz, Feldspar, and Mica)

Granite

Granite (Felsic Plutonic Rock)

Pink Granite Pebble

Granite (Phaneritic igneous rock)

Granite Pebble

Granite (phaneritic igneous rock)

Pink Granite

Granite (Phaneritic intrusive rock)

Vesicular Basalt (River Pebble)

Basalt (Mafic volcanic rock)

Weathered vesicular basalt (probable)

Basalt; primarily plagioclase, clinopyroxene, and iron-rich olivine, with secondary weathering minerals

Granite

Granite (composed of Quartz, Felspar, and Mica)

Basalt

Basalt (Mafic volcanic rock)

Basalt with Epidote Veins

Mafic Igneous Rock (Basalt)

River Cobble (Basalt or Greywacke)

Extrusive Mafic Igneous Rock (likely Basalt)

Basalt with Quartz/Calcite Inclusion

Aphanitic Mafic Igneous Rock (Basalt) with SiO2 or CaCO3 vein

Light-colored granite or granitic gneiss

Granite; primarily quartz (SiO₂), feldspar, and minor mica, possibly with gneissic fabric

Porphyritic Andesite or Dacite (tumbled pebble)

Porphyritic Igneous Rock (likely Andesite or Dacite)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartzite

Quartzite (SiO2-rich metamorphic rock)

Granite (Background) and Quartzite/River Pebble (Foreground Heart)

Phaneritic Felsic Igneous Rock (Granite background)

Likely pink feldspar-rich granite or pegmatite

Granite/pegmatite; primarily quartz (SiO₂), alkali feldspar (KAlSi₃O₈), and plagioclase feldspar

Chert (River Pebble)

Chert (Silica, SiO2)

Weathered basaltic cobble

Basalt, likely amygdaloidal or vesicular basalt

Quartzite Pebble

Quartzite (SiO2)

Gneissic granite / granitic gneiss

Quartz–feldspar–mica gneiss; composition commonly quartz (SiO₂), feldspars, and biotite/muscovite

Limestone Pebble

Limestone (Calcium Carbonate, CaCO3)

Sandstone

Quartz Sandstone (predominantly)

Shale

Shale (clastic sedimentary rock)

Shale

Shale (Lutite)

Shale

Fissile mudrock (composed primarily of clay minerals and quartz)

Quartz-rich breccia or vein quartz fragment

Quartz (SiO₂), likely with iron-oxide staining and attached host rock

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline quartz (SiO₂), possibly with mica and feldspar

Quartz-rich metamorphic rock (likely quartzite)

Quartzite, dominantly crystalline SiO₂, with probable iron-oxide staining and minor feldspar/mica

Polished copper-bearing rock, likely cuprite-rich copper ore

Cuprite (Cu₂O) with native copper and iron-oxide matrix, probable

Likely quartz-rich metamorphic rock (quartzite or milky quartz)

Quartzite; predominantly quartz (SiO₂), possibly with feldspar and iron-oxide staining

Blue sodalite-bearing rock, likely sodalite in nepheline syenite

Sodalite (Na₈Al₆Si₆O₂₄Cl₂), possibly in nepheline syenite

Dark weathered igneous rock, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Weathered quartz-rich rock, likely quartzite or quartz vein

Quartzite; predominantly quartz (SiO₂), possibly iron-oxide stained

Quartz-rich metamorphic rock, likely milky quartz or quartzite

Quartz (SiO₂); possibly quartzite composed predominantly of recrystallized quartz

Granite (likely weathered granitic rock)

Granitic rock, chiefly quartz + feldspar + mica (variable composition)

Pyrite-bearing metamorphic rock (probable schist or quartzite)

Quartz–mica schist with disseminated pyrite; approximate composition SiO₂ + phyllosilicates + FeS₂

Quartz geode or drusy quartz cluster

Quartz (silicon dioxide, SiO₂), likely microcrystalline quartz lining a cavity

Weathered greenish rock fragment

Indeterminate; possibly epidote- or chlorite-bearing altered silicate rock

Weathered iron-rich rock, possibly meteorite

Uncertain; likely goethite/hematite-rich material, with meteorite possibility