Industrial Byproduct (Anthropogenic Rock)

Red Sandstone

Arenite (SiO2 with Fe2O3)

Unidentified brown rock fragment

Indeterminate from image; likely a weathered iron-rich lithic fragment

Likely polished red-and-blue jasper (identification uncertain from the image)

Jasper, an opaque, microcrystalline variety of quartz (SiO₂)

Schist

Mica Schist

Mica-rich granite (likely weathered pegmatitic granite)

Granite, chiefly quartz (SiO₂), feldspar, and mica (muscovite and/or biotite)

Mica Schist

Metamorphic Schist

Muscovite Mica Schist

Metamorphic Rock (Muscovite-Biotite Schist)

Rounded river pebble

Unidentified lithic pebble; exact rock type cannot be determined from the image

Likely beach-worn glass and a pebble

The brown piece appears to be weathered glass (amorphous SiO₂-rich material); the pale piece is likely a small quartz-rich stone, possibly milky quartz.

Anthracite Coal

Anthracite (Carbon-based metamorphic rock)

Fossil brachiopod

Brachiopoda; likely a spiriferid or strophomenid brachiopod

Pumice

Pumice (volcanic glass froth)

Blue-green rough mineral specimen (identity uncertain)

Undetermined; the image is insufficient for a reliable mineral identification

Agate (Chalcedony)

Silicon Dioxide (SiO2)

Tumbled, iron-stained quartz-rich pebble

Likely quartz/chalcedony with iron-oxide staining; exact rock type cannot be determined from the image

Blue Sapphire

Corundum (Al2O3)

Polished ocean jasper (orbicular jasper), probable

Silicified orbicular rhyolite; chiefly microcrystalline quartz (SiO₂)

Tumbled brown jasper (likely)

Microcrystalline quartz, SiO₂; jasper is an opaque variety of chalcedony

Rounded, weathered pebble (likely quartz-rich rock)

Indeterminate from the image; possibly quartzite or quartz-rich sandstone

Rounded brown river pebble

Indeterminate lithic fragment; possibly weathered sandstone, mudstone, or basalt

Quartzite

Quartzite (SiO2)

Pumice

Pumicite / Vesicular Rhyolite

Basalt (Glassy)

Basalt (Aphanitic-Glassy texture)

Quartzite

Quartzite (primarily SiO2)

Pink Quartzite

Quartzite (High-silica metamorphic rock)

Granite

Granite (Felsic Intrusive Igneous Rock)

Granodiorite

Granodiorite (phaneritic intrusive igneous rock)

Bituminous Coal

Organic Sedimentary Rock (Carbon-based)

Gabbro

Phaneritic mafic intrusive igneous rock

Weathered brown pebble, possibly basalt or iron-rich chert

Provisional identification: fine-grained basalt (plagioclase–pyroxene), potentially coated by iron oxides; exact identification requires testing

Quartz Cluster

Silicon Dioxide (SiO2)

Iron-stained quartz vein rock

Quartz-rich rock with iron-oxide/hydroxide coatings (hematite/goethite); exact host rock undetermined

Tumbled milky quartz

Quartz, silicon dioxide (SiO₂), likely milky or translucent quartz

Milky Quartz

Crystalline Silicon Dioxide (SiO2)

Iron-stained quartz or quartzite fragment

Quartz (SiO₂), possibly iron-oxide-stained quartzite

Red garnet (possible almandine or pyrope), cut/polished

Garnet-group silicate; likely almandine, Fe₃Al₂(SiO₄)₃, or pyrope, Mg₃Al₂(SiO₄)₃

Yellow Quartzite (River Pebble)

Quartzite (primarily Silicon Dioxide, SiO2)

Rounded gray pebble

Indeterminate; likely fine-grained quartz-rich silicate rock

Quartz-rich pebble

Likely milky quartz or quartz-rich vein rock (SiO₂); exact identification is uncertain from the photo

Quartz geode fragment

Microcrystalline and drusy quartz, SiO₂, likely in a weathered carbonate or volcanic host

Black-and-white bicolored pebble

Likely basalt with a pale felsic or carbonate coating/inclusion; exact identification requires testing

Quartzite Pebble

Metamorphic Quartzite (SiO2)