Sedimentary Rock (Possibly A Conglomerate Or Coarse Grained Sandstone)

Weathered limestone or calcareous sandstone

Calcitic carbonate rock, likely limestone (CaCO₃), possibly slightly dolomitic

Light-colored sandstone or quartzite

Quartz-rich sandstone; possibly weakly metamorphosed quartzite

Dark igneous rock, likely basalt or diabase, with a second purplish specimen

Basalt/diabase; exact identification is uncertain from the photograph

Brick fragment (Man-made material)

N/A (Fired clay)

Tumbled dark igneous rock, possibly gabbro or basalt

Likely mafic rock composed chiefly of pyroxene and plagioclase; exact identification requires testing

Weathered quartz-bearing rock, possibly gneiss or quartzite

Indeterminate; likely quartz-rich metamorphic rock containing quartz and feldspar

Weathered brown rock fragment

Indeterminate; possibly iron-stained sandstone or weathered limestone

Granite or granitic gneiss

Quartz–feldspar–mica granitoid; possibly foliated gneiss

Mixed river stones; foreground likely sandstone

Quartz-rich sandstone, with associated rounded quartzite/chert and other cobbles

Tumbled pegmatitic granite

Coarse-grained granite/pegmatite, chiefly quartz, feldspar, and biotite or amphibole

Quartz-rich sandstone or quartzite cobble

Quartz arenite; possibly weakly metamorphosed quartzite (SiO₂-dominant)

Weathered granitic or feldspathic pebble

Likely granite/granodiorite; quartz–feldspar–mica aggregate

Rounded brown river cobble

Likely iron-stained quartz-rich sandstone or weathered conglomeratic rock; exact identification requires testing

Quartz Pebble (Quartzite Pebble)

Silicon Dioxide (SiO2)

Likely weathered sandstone or iron-rich sedimentary rock

Quartz-rich sandstone, possibly ferruginous sandstone; exact identification requires testing

Polymictic conglomerate

Conglomerate; clast-supported polymictic conglomerate in a dark matrix

Quartz-rich metamorphic rock, likely quartzite

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

Quartzite (or Quartz Rich Conglomerate)

Quartzite (SiO2 silicon dioxide)

Weathered sandstone or volcanic rock fragment

Indeterminate; likely quartz–feldspar-rich sandstone, possibly altered volcanic rock

Weathered quartz-rich sandstone or quartzite

Quartzite (predominantly SiO₂), possibly strongly cemented sandstone

Dark coarse-grained rock, likely gabbro or amphibolite

Gabbro (plutonic mafic rock; mainly plagioclase and pyroxene), possibly amphibolite if metamorphosed

Chert Breccia

Brecciated Chert (Sedimentary Rock)

Possible sandstone cobble or weathered basalt

Indeterminate lithic specimen; likely quartz-rich sandstone, possibly weathered basalt

Weathered sandstone or arkose

Quartz–feldspar clastic sedimentary rock; likely arkosic sandstone

Weathered granite or granitic gneiss

Granite; primarily quartz, feldspar, and mica (approximate visual identification)

Granite retaining-wall blocks

Granite, principally quartz, potassium feldspar, plagioclase, and mica

Coarse Sandstone

Arenite (SiO2 based)

Likely weathered limestone or calcareous sandstone

Calcite-rich carbonate rock; predominantly CaCO₃, possibly micritic limestone

Gravel / Small Pebble

Rock Fragment (Gravel)

Reddish sandstone or iron-stained quartzite pebble

Likely ferruginous sandstone; possibly quartzite, composed mainly of quartz (SiO₂) with iron oxides

Gneiss

High-grade regional metamorphic rock

Quartz–mica metamorphic rock, likely schist

Quartz–muscovite/biotite schist; predominantly SiO₂ quartz with phyllosilicate micas

Sandstone (Iron-stained)

Arenite with Limonite/Hematite staining

Conglomeratic basalt (rounded volcanic breccia/pebble)

Basaltic conglomerate or polymict volcanic breccia; predominantly plagioclase–pyroxene basalt with lighter felsic or weathered clasts

Weathered quartz-rich rock, likely sandstone or quartzite

Quartz-dominated clastic rock; possibly quartzite (SiO₂-rich)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Light-colored weathered stone, possibly limestone or quartz-rich rock

Indeterminate; likely calcitic limestone (mostly CaCO₃) or quartz sandstone (SiO₂)

Weathered quartz-rich rock, likely arkose or quartzite

Quartz-dominant siliciclastic rock; probable arkose (quartz + feldspar), possibly weakly metamorphosed quartzite

Dark, coarse-grained rock (possibly mafic igneous rock)

Undetermined; potentially basaltic or gabbroic material

Conglomerate (likely polymictic conglomerate)

Clastic sedimentary rock composed of rounded lithic and mineral clasts in a finer matrix; commonly quartz, feldspar, chert, and volcanic fragments cemented by silica, calcite, or iron oxides

Rounded iron-rich sandstone or ferruginous conglomeratic rock

Quartz-rich sandstone, locally cemented by iron oxides (hematite/goethite)

Conglomerate

Polymictic clast-supported conglomerate, likely ferruginous