Sedimentary Or Igneous Fragment

Shale fragment

Shale (clay mineral rich sedimentary rock)

Quartz (Crystal)

Silicon Dioxide (SiO2)

Quartz (Small Fragment)

Silicon Dioxide (SiO2)

Fragmented Sedimentary Pebble

Clastic Sedimentary Specimen

Pebble

Lithified rock fragment / Sedimentary clast

Mixed River Pebbles

Clastic Sedimentary Alluvial Deposit / Polymictic Conglomerate Clasts

Small white shell fragment

Calcium-carbonate shell, likely aragonite or calcite; exact organism undetermined

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Magnetite

Magnetite (Fe3O4)

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Small dark gray stone, possibly slate or basalt

Unidentified fine-grained rock; image is insufficient for confident identification

Small quartz-rich rock fragment

Indeterminate quartz- and feldspar-bearing rock; exact identification is not possible from the image

Dark gray fine-grained rock fragment

Possibly andesite or basalt; exact identification is not possible from the image alone

Small weathered rock fragment

Unidentified iron-stained, fine-grained rock; exact composition cannot be determined from the image

Reddish-brown, iron-stained rock fragment

Indeterminate; possibly weathered porphyritic volcanic rock

Likely quartz-rich rock fragment

Indeterminate; possibly quartz-bearing granite or quartzite

Small brown rock fragment; exact identification uncertain

Unidentified fine-grained lithic fragment

Black Obsidian

Volcanic Glass (SiO2 with impurities)

Fossilized shell fragment, likely bivalve

Bivalvia indet.; commonly preserved as calcite (CaCO₃) shell material

Chalcedony Geode Fragment

Microcrystalline Quartz (SiO2)

Weathered sandstone (probable arkosic sandstone)

Clastic sandstone, mainly quartz (SiO₂) with feldspar and iron-oxide cement

Breccia

Sedimentary Breccia

Unidentified weathered rock fragments

Likely mixed silicate rocks; specific identification requires testing

Weathered yellow-brown rock pebble

Undetermined; possibly iron-oxide-stained sandstone or mudstone

Small weathered rock fragment

Indeterminate; possibly limestone or altered volcanic rock

Small clear-to-milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Weathered rock fragment (likely granite or granitic gneiss)

Undetermined felsic rock; possibly quartz–feldspar granite

Milky quartz / quartz vein fragment

Quartz, silicon dioxide (SiO₂)

Pebble

Lithic fragment

Pebble

Lithic fragment

Pebble

Lithic fragment

Small flint/chert fragment (tentative)

Chert, microcrystalline quartz (SiO₂)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Weathered granite or granitic gneiss

Granite, chiefly quartz, feldspar, and mica; exact identification is uncertain from the photograph

Chert (Common Opal variant)

Silicon Dioxide (SiO2)

Clear quartz chips

Quartz (silicon dioxide, SiO₂)

Conglomeratic or porphyritic basalt cobble

Likely vesicular basalt with weathered feldspar/mafic inclusions; exact identification requires testing

Tumbled feldspar (likely peach moonstone/sunstone)

Potassium–sodium feldspar; likely orthoclase or oligoclase, (K,Na)AlSi₃O₈

Likely weathered quartz-bearing rock fragment

Indeterminate; appears to contain quartz (SiO₂) with iron-oxide staining, possibly from quartzite, granite, or pegmatite