This Is Not A Rock Or Mineral

Shale

Shale (Lutite)

Likely greenstone (metamorphosed basalt)

Metabasalt; commonly composed of chlorite, actinolite, epidote, and albite

Granite River Rock

Intrusive igneous rock (composed mainly of quartz, alkali feldspar, and plagioclase)

Granite Pebble

Granite (Plutonic Igneous Rock)

Quartz Vein in Basalt or Mafic Rock

Silicon Dioxide (SiO2) vein in volcanic/mafic matrix

Greenstone pebble

Likely chlorite- and/or actinolite-bearing metamorphic rock; exact composition cannot be determined from the image.

Rounded river pebble, likely quartz-rich stone

Unidentified lithic clast; exact mineralogy cannot be determined from the image

Quartz Geode

Silicon Dioxide (SiO2)

Note: No specimen visible

Weathered granite or granitic gneiss

Granite; primarily quartz, feldspar, and mica

River Pebble (Granite/Gneiss)

Granitic Pebble / Quartz-Feldspar Aggregate

Red Sandstone

Sandstone (principally Quartz with Iron Oxide coating)

Small rounded pebble, likely quartz-rich river or beach stone

Unidentified lithic pebble; exact rock type cannot be determined from the image

Greenstone, likely altered basalt

Metabasalt (chlorite–actinolite–epidote assemblage), likely greenschist-facies greenstone

Gneiss

Foliated Metamorphic Rock (Gneiss)

Granodiorite (Weathered)

Granodiorite

Unidentified pale mineral or rock specimen

Indeterminate; image quality prevents reliable mineral identification

Vesicular Basalt / Scoria pebble

Extrusive igneous rock with amygdaloidal infilling

Iron-rich breccia or weathered ironstone

Goethite–hematite-bearing limonite, possibly with quartz and altered rock fragments

Sandstone (with Rock Art)

Sandstone (Clastic Sedimentary Rock)

Quartz Vein in Basalt or Slate

Hydrothermal quartz vein traversing mafic host rock

Granite

Granite, a felsic intrusive igneous rock composed chiefly of quartz, feldspar, and mica

Biotite-bearing granite

Granite, composed chiefly of quartz, feldspar, and biotite; exact identification is uncertain from the photo.

Orbicular granite (likely rapakivi-type granite)

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Granite

Intrusive Igneous Rock

Likely garnet-bearing rock (possibly almandine garnet in matrix)

Garnet, likely almandine (Fe₃Al₂Si₃O₁₂); host rock cannot be determined from the image

Granite

Granite

Likely serpentine

Serpentine-group minerals, chiefly antigorite, lizardite, or chrysotile; approximate formula Mg₃Si₂O₅(OH)₄

Breciated Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Rounded quartz-rich river pebble

Likely quartz-bearing rock; exact lithology cannot be determined from the photograph

Carnelian agate

Cryptocrystalline quartz (SiO₂), iron-oxide-bearing chalcedony

Small brown mineral fragment (undetermined)

Unidentified; image detail is insufficient for a reliable species identification

Sandstone

Sedimentary Rock (Quartz Sandstone)

Beach Pebble (Basalt/Porphyry)

Weathered Basalt or Porphyry

Granite / Quartzite Specimen

Granite / Quartz (SiO2 with Feldspar and Mica)

Sandstone (with Iron Staining)

Clastic sedimentary rock (SiO2 with Fe2O3 oxides)

Wishing Stone (Basalt or Siltstone with Quartz/Calcite Vein)

Basalt (SiO2+MgO+FeO) or Siltstone with a Quartz (SiO2) or Calcite (CaCO3) vein

Gneiss

Gneiss (Metamorphic Rock)

Mixed Mineral Assortment (Pyrite, Kyanite, Agate, Jasper)

FeS2 (Pyrite), Al2SiO5 (Kyanite), SiO2 (Agate/Jasper)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within metamorphic/igneous matrix

Granodiorite

Granodiorite (Intermediate intrusive igneous rock)

Sandstone with Quartz Vein

Arenite with Crystalline Silica (SiO2)