Rock

Sandstone (River Cobble)

Sandstone (principally composed of Quartz, SiO2)

Quartzite (Yellow/Orange variety)

Quartzite (primarily SiO2)

Porphyry

Porphyritic igneous rock

Basalt with Alteration Crust

Basalt (SiO2 range 45-52%)

Leopard Skin Jasper

Orbicular Jasper (Silicon Dioxide, SiO2)

Basalt

Mafic Igneous Rock (composed primarily of plagioclase feldspar and pyroxene)

Basalt

Mafic extrusive igneous rock

Clear Quartz (Cut/Faceted Gemstone)

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Basalt

Basalt (Mafic volcanic rock)

Basalt Cobble

Aphanitic Mafic Igneous Rock (Basalt)

Basalt River Cobble

Basalt (Mafic volcanic rock)

Milky Quartz with Chlorite Schist Inclusions

Quartz (SiO2) with Chlorite Group silicates (typically (Mg,Fe)3(Si,Al)4O10(OH)2)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, Mica)

Gneiss

Felsic, quartz–feldspar gneiss

Iron-stained rock, likely limonite-rich weathered stone

Limonite (iron oxyhydroxides, chiefly goethite) coating or staining a rock of uncertain composition

Pink granite pebble

Granite, a coarse-grained felsic intrusive igneous rock

Rounded granitic gneiss pebble

Quartz–feldspar–biotite gneiss (tentative; exact identification requires closer inspection)

Granite-like cobble

Granitoid, likely biotite granite or granodiorite

Porphyritic granite (likely orbicular/porphyritic granitoid)

Quartz–feldspar granitoid; commonly composed of K-feldspar, plagioclase, quartz, and biotite/hornblende

Likely silver-gray granite or granitic gneiss fragment

Granite; primarily quartz (SiO₂), feldspar, and mica (exact identification uncertain from image)

Quartz Druzy (Geode Fragment)

Silicon Dioxide (SiO2)

Polished greenstone pebble

Likely chlorite- or actinolite-bearing greenstone (metamorphosed mafic rock)

Quartz Geode (likely within Limestone or Dolomite matrix)

Quartz (SiO₂)

Small rounded stone, likely a pebble

Unidentified fine-grained lithic pebble; image alone does not support a reliable mineral or rock-species identification

Yellow Agate (Banded Chalcedony)

Silicon Dioxide (SiO2)

Wishing Rock (Quartz Vein in Host Rock)

Silicon dioxide (SiO2) vein in various host rocks

Quartz Vein in Metamorphic Rock

Quartzite or Schist host with Quartz (SiO2) intrusion

Quartz-veined Metamorphic Pebble

Silicate-rich metamorphic rock with quartz veins (SiO2)

Weathered iron-stained rock fragment

Uncertain from the image; likely an iron-oxide-stained, quartz- and feldspar-bearing rock

Unknown Tumbled Stone

Unknown (Too Blurry)

Quartz Geode

Silicon Dioxide (SiO2) within a sedimentary or volcanic shell

Quartz Geode

Silicon Dioxide (SiO2)

Tumbled yellow jasper (probable)

Jasper, an opaque microcrystalline variety of quartz; chiefly SiO₂ with iron-oxide inclusions

Greenstone pebble (likely altered basalt or serpentine)

Greenschist-facies mafic rock; commonly chlorite–actinolite–epidote ± serpentine

Vesicular Basalt (or Scoria)

Vesicular Basalt

Shale / Mudstone

Laminated Mudrock (Siliciclastic Sedimentary Rock)

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Agate Geode

Silicon Dioxide (SiO2) - Chalcedony variety

Tumbled serpentine with dark magnetite/chromite matrix

Serpentinite; chiefly antigorite/lizardite, Mg3Si2O5(OH)4, with magnetite and possibly chromite

Basalt

Basalt

Gneiss

High-grade regional metamorphic rock (Foliated)