Sedimentary Rock (Possibly A Conglomerate Or Coarse Grained Sandstone)

Quartz-rich metamorphic rock, likely quartzite

Quartzite (predominantly quartz, SiO₂); identification is tentative from the image

Sandstone

Sandstone (SiO2 dominated)

Biotite-rich granite or granitic gneiss

Quartz–feldspar–biotite granite; possibly foliated granitic gneiss

Sandstone

Arenite (composed primarily of SiO2)

Sandstone

Arenite (SiO2 principal)

Foliated gneiss, possibly migmatitic gneiss

Gneiss; primarily quartz, feldspar, and mica (biotite/muscovite), with possible amphibole

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (SiO2 based)

Weathered iron-rich rock, possibly limonite-bearing sandstone or ironstone

Limonite/goethite-rich ferruginous sandstone; composition uncertain from the photograph

Granite (likely weathered quartz-bearing granite)

Granite; primarily quartz, feldspar, and mica/amphibole

Weathered schist or foliated metamorphic rock

Mica schist, possibly phyllite; exact identification requires a fresh surface and testing

Polymict conglomerate

Clastic conglomerate, likely polymictic and matrix-supported

Sandstone

Quartzose Sandstone (Sedimentary Rock)

Asphalt Concrete (Bituminous Conglomerate)

Anthropogenic Bituminous Conglomerate

Shale (possibly)

Shale (fine-grained clastic sedimentary rock)

Mixed collection of natural stones

Several unidentified lithologies, likely including basalt, granite, quartzite, sandstone, and weathered metamorphic rocks

Quartz-bearing metamorphic rock, likely quartzite or hornfels

Quartz (SiO₂) in a fine-grained silicate matrix; exact rock identification requires testing

Rounded river pebble (likely fine-grained sandstone or quartzite)

Indeterminate from image; likely quartz-rich sandstone, possibly quartzite

Weathered granite or granitic pegmatite cobble

Granite/granitic rock, composed mainly of quartz (SiO₂), feldspar, and minor biotite or other dark minerals; the reddish-brown areas may be iron-oxide staining or weathered accessory minerals

Coarse-grained granite or granitic gneiss

Granite; predominantly quartz, potassium feldspar, plagioclase, and dark biotite/hornblende

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily Quartz, SiO2)

Sandstone

Arenite (SiO2 primarily)

Likely quartz-rich pebble fragment

Quartz (SiO₂), possibly milky quartz or quartzite; the photo is insufficient to distinguish them confidently

Iron-rich sandstone or weathered ironstone fragment

Ferruginous sandstone; chiefly quartz (SiO₂) cemented or stained by iron oxides such as hematite/goethite

Quartz Breccia with Iron Staining

Tectonic or Sedimentary Breccia (SiO2 with Fe2O3)

Feldspathic sandstone or arkose

Arkose; chiefly quartz (SiO₂), potassium feldspar (KAlSi₃O₈), and minor lithic grains in a silica/clay cement

Sandstone

Arenite

Gravel and Pebbles

Unconsolidated rock fragments (clastic sediment)

Shale or Mudstone River Pebble

Argillaceous sedimentary rock

Sandstone (Micaceous)

Clastic Sedimentary Rock (primarily SiO2 with Mica)

Asphalt Chunk (with aggregate)

Bituminous concrete / Anthropogenic conglomerate

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 predominantly)

Sandstone Pebble

Sandstone (Siliciclastic Sedimentary Rock)

Greywacke (River Pebble)

Dirty Sandstone (SiO2 with lithic fragments)

Likely basalt or another dark, coarse-grained igneous rock

Possibly olivine-bearing basalt (plagioclase, pyroxene, and possibly olivine); identification is uncertain from the photo

Reddish-brown rounded pebble, likely iron-stained sandstone or chert

Probable quartz-rich sandstone (SiO₂), possibly ferruginous chert; exact identification requires testing

Shale

Fissile Clay-dominant Mudrock (SiO2, Al2O3, K2O, Na2O, CaO, MgO)

Diorite (possibly Orbicular Diorite or Porphyritic Diorite)

Intermediate Phaneritic Igneous Rock

Red Sandstone Pebble

Arenite (Iron-oxide stained)

Weathered granite or granitic gneiss fragment

Quartz–feldspar–mica aggregate; likely granite (possibly gneiss)

Weathered granite or granitic gneiss

Quartz–feldspar–mica aggregate; possibly foliated granitic gneiss

Granite

Coarse-grained felsic intrusive rock, chiefly quartz, alkali feldspar, plagioclase, and mica (biotite/muscovite).