Sedimentary Or Igneous Fragment

Quartz (Milky or Cloudy)

Silicon Dioxide (SiO2)

Quartz pebble or quartz-rich fragment

Quartz (silicon dioxide, SiO₂), possibly iron-stained or included

Bivalve Shell Fragment (Biogenic Calcite/Aragonite)

Calcium carbonate (CaCO3, primarily aragonite/calcite)

Small tan rock fragment

Unidentifiable lithic fragment; mineral composition undetermined

Quartz-rich sandstone or quartzite fragment

Quartz (SiO₂) with iron-oxide staining; possibly weakly metamorphosed quartzite

Weathered dark igneous rock fragment

Likely basalt or andesite; exact identification is uncertain from the photograph

Granite Sand (Decomposed Granite)

Grus / Quartz-Feldspar Detritus

Conglomerate

Clastic sedimentary rock (Conglomerate)

Likely anthracite coal fragments

Anthracite; predominantly carbon (C), with minor mineral ash

Green Fluorite

Calcium Fluoride (CaF2)

Granitic Gneiss

Gneiss (containing Potassium Feldspar and Quartz)

Polymict breccia

Volcanic breccia (clast-rich pyroclastic rock), compositionally likely andesitic to basaltic

Clear Quartz

Silicon Dioxide (SiO2)

Quartz (Clear Quartz)

Silicon Dioxide (SiO2)

Raw Fluorite

Calcium Fluoride (CaF2)

Conglomerate (pebble-to-cobble gravel)

Polymictic conglomerate; clast-supported conglomerate in a sandy or silty matrix

Quartz

SiO2 (Silicon Dioxide)

Gneiss

Gneiss (Foliated Metamorphic Rock)

Gneiss

Orthogneiss / Paragneiss

Fossilized bivalve shell fragment

Bivalvia; commonly aragonite or calcite (CaCO₃), often recrystallized during fossilization

Fossiliferous Limestone

Biogenic Sedimentary Rock (Calcium Carbonate, CaCO3)

Unidentified Pebble

Lithic fragment

Pebble

Lithic fragment

Generic Rock Fragment

Rock Fragment

Clear Quartz

Silicon Dioxide (SiO2)

Folded Schist / Gneiss (Metamorphic Rock)

Regional Metaphoric Folded Outcrop (predominantly Schist/Gneiss)

Likely smoky quartz or quartz-rich tumbled fragment

Quartz, silicon dioxide (SiO₂), possibly smoky quartz

Weathered iron-rich stone, possibly sandstone or ironstone

Indeterminate; likely quartz-rich sandstone with iron-oxide cement, possibly hematite/goethite

Rounded quartz-rich pebble, possibly chert or weathered sandstone

Indeterminate siliciclastic rock; likely microcrystalline quartz (SiO₂) or quartz-feldspar sandstone

Basalt Fragment

Extrusive Igneous Rock

Weathered granite fragment

Granite, chiefly quartz–feldspar–mica aggregate

Unidentified orange-brown rock fragment

Likely weathered iron-rich volcanic rock or ochre-bearing material; exact identification is impossible from the blurred image

Orange feldspar pebble (likely potassium feldspar)

Likely orthoclase or microcline, KAlSi₃O₈

Milky quartz

Quartz, silicon dioxide (SiO₂)

Fossiliferous limestone (likely crinoidal or shell limestone)

Calcite-rich limestone; predominantly CaCO₃, with visible fossil fragments

Quartz

Silicon Dioxide (SiO2)

Biotite-bearing metamorphic rock, likely schist

Mica schist; chiefly quartz, feldspar, and biotite mica

Weathered sandstone

Quartz–feldspar arenite, commonly ferruginous sandstone

Clear Quartz

Silicon Dioxide (SiO2)

Light-colored, weathered rock fragment

Undetermined; possibly weathered granite or granitic rock

Weathered rock fragment, possibly basalt

Unidentified fine-grained mafic rock; basalt is a tentative visual identification

Small gray-green stone, likely a quartz-rich rock fragment

Undetermined silicate rock; image lacks enough detail for a reliable species-level identification