Sedimentary Rock (Possibly A Conglomerate Or Coarse Grained Sandstone)

Puddingstone (Jasper Conglomerate)

Conglomerate (specific type: Jasper Conglomerate or Hertfordshire Puddingstone)

Coarse Sandstone Pebble

Clastic Sedimentary Rock (Sandstone)

Rounded tan cobble, likely quartzite or sandstone

Quartzite (mostly quartz, SiO₂); possibly quartz-rich sandstone

Rounded reddish-brown pebble

Likely ferruginous sandstone or iron-rich quartzite; exact identification requires a fresh surface and tests

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite, composed predominantly of quartz (SiO₂), possibly with feldspar and mica impurities

Likely weathered sandstone or iron-rich volcanic rock

Indeterminate from photograph; probable ferruginous sandstone, possibly altered volcanic rock

Dark coarse-grained rock, likely basalt or gabbro

Basalt (fine-grained) or gabbro (coarse-grained), composed mainly of plagioclase feldspar and pyroxene

Weathered yellow-brown rock pebble

Undetermined; possibly iron-oxide-stained sandstone or mudstone

Breccia (likely quartz-cemented polymict breccia)

Clastic breccia; chiefly angular quartz/feldspar or carbonate clasts in a silica- or carbonate-rich matrix

Graywacke

Lithic Sandstone (Graywacke)

Graywacke

Graywacke Sandstone

Arkosic Sandstone

Arkose (Clastic Sedimentary Rock)

Biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite granite; possibly weakly foliated granitic gneiss

Puddingstone (Jasper-Conglomerate)

Jasper Conglomerate (SiO2 matrix with Jasper clasts)

Conglomerate

Conglomerate

Likely iron-rich sandstone or ironstone pebble

Ferruginous sandstone (quartz-rich sandstone cemented by iron oxides); exact identification requires testing

Siltstone with Weathering Rind

Siltstone (composed of microscopic quartz and clay minerals)

Weathered sandstone

Quartz-rich sandstone (clastic sedimentary rock)

Weathered sandstone or siltstone pebble

Indeterminate siliciclastic sedimentary rock, likely quartz-rich sandstone (SiO₂-dominated)

Graywacke with Quartz Vein

Lithic Sandstone (Graywacke)

Gneiss

Gneiss (Foliated Metamorphic Rock)

Puddingstone

Conglomerate

Breccia

Breccia (Clastic sedimentary rock)

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz-feldspar aggregate, potentially granitic or quartzitic material

Weathered sandstone or limestone fragment

Likely quartz-rich sandstone; possibly calcarenite or weathered limestone

Sandstone

Clastic Sedimentary Rock (composed mostly of quartz, SiO2)

Brown sandstone or weathered iron-rich sedimentary rock

Likely quartz-rich sandstone, potentially ferruginous sandstone; exact identification requires testing

Mixed stream gravel and common rock specimens

Predominantly quartz-rich granitoid, quartzite, sandstone, shale/slate, and mafic volcanic fragments; exact species cannot be determined confidently from the image

Fossiliferous limestone

Bioclastic limestone (calcite-rich carbonate rock)

Sedimentary Pebble

Sedimentary Rock Fragment

Quartzite

Metamorphic Rock (Mainly SiO2)

Banded gneiss

Quartz–feldspar gneiss, possibly biotite-bearing; exact identification requires testing

Likely weathered gneiss or granite fragment

Quartz–feldspar–mica aggregate; probably granitoid gneiss, identification uncertain from the photograph

Conglomerate (polymictic, possibly metamorphosed)

Polymictic conglomerate; clasts cemented in a dark, likely quartz-rich matrix

Puddingstone

Conglomerate

Rounded river pebble

Unidentified fine-grained clastic rock, possibly sandstone or mudstone

Pink granite (weathered fragment)

Granite, primarily quartz–feldspar–mica (pink alkali feldspar, plagioclase, quartz, biotite/hornblende)

Weathered quartz-rich rock, possibly quartzite

Quartzite (tentative identification; exact rock type cannot be confirmed from the image)

Quartz (with inclusions / Sandstone fragment)

Silicon Dioxide (SiO2)

Greywhacke (River Pebble)

Graywacke (immature sandstone)

Dark, coarse-grained rock (possibly diorite or amphibolite)

Undetermined; likely a mafic to intermediate rock containing plagioclase and dark amphibole or pyroxene

Rounded river pebble, likely quartz-rich sandstone or weathered igneous rock

Indeterminate; possibly quartzite, sandstone, or fine-grained granitic rock