Mineral, Specifically A Rock Fragment

Polished red-orange agate and pale porous mineral specimen

Agate (microcrystalline quartz, SiO₂); upper piece likely calcite or aragonite, but identification is uncertain from the image

Grey Pebble (Sandstone / Quartzite Pebble)

Sedimentary rock (primarily Quartz - SiO2)

Sandstone

Arenite

Amethyst on Basalt

Silicon dioxide (SiO2) with trace Iron

Yellow Jasper

Silicon Dioxide (SiO2 with iron oxide inclusions)

Quartz-rich metallic-looking pebble

Likely quartz or quartzite; exact identification is uncertain from the blurred image

Coquina / Shelly Sandstone

Calcareous Sandstone / Coquina

Unidentified small rock fragment

Likely quartz-rich material; exact identification is indeterminate from the image

Sandstone with Iron Staining

Arenite (SiO2 with Fe2O3)

White beach pebbles, likely milky quartz

Probably quartz (SiO₂); exact identification is uncertain from the image

Weathered quartz-rich rock fragment

Indeterminate; likely quartz-bearing granitoid or quartzite

Pumice or vesicular volcanic rock

Pumice; predominantly volcanic glass (silica-rich, commonly rhyolitic to dacitic)

Pink Granite

Phaneritic intrusive igneous rock (high Orthoclase Feldspar content)

Quartz-rich rock fragment, possibly granite or quartzite

Indeterminate quartz-bearing silicate rock; likely quartz (SiO₂) with feldspar and/or mica

Sandstone Pebble

Sedimentary Rock (Quartzose Sandstone)

Quartz

Silicon Dioxide (SiO2)

Black-and-white bicolored pebble

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

Granite (Pink/Red Granite)

Phaneritic Felsic Igneous Rock

Quartz Druzy Geode Fragment

Silicon Dioxide (SiO2)

Granite fragment

Granite

Breccia

Clastic Breccia

Small rounded mineral pebble, possibly quartz

Uncertain; likely microcrystalline or crystalline SiO₂ (quartz), potentially with iron-oxide staining

Sandstone Pebble

Sedimentary Rock (Quartz Arenite)

Banded Agate (Onyx variety)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Weathered granitic rock fragment

Granite, likely quartz–feldspar–mica aggregate

Sandstone

Arenite (SiO2 based typically)

Sandstone and Mixed Rock Assemblage

Clastic Sedimentary Rock / Quartz Arenite

Likely quartz-bearing rock fragment

Quartz (SiO₂), possibly in a weathered granitoid or metamorphic matrix

Pink Granite

Intrusive Igneous Rock (Granitic)

Tiny amber-colored crystal fragment

Indeterminate; possibly quartz, feldspar, mica, or a sulfide mineral

Pink Granite

Felsic Plutonic Rock (primarily Quartz, Potassium Feldspar, and Plagioclase)

Sandstone

Arenite

Sandstone

Arenite (Silicon Dioxide with various mineral cements)

Sandstone

Arenite

Sandstone

Sandstone (Silicon dioxide, SiO2 based)

Sandstone

Arenite (typically SiO2 based)

Sandstone/Quartzite

Sedimentary Rock (composed mainly of SiO2)

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (composed primarily of SiO2)

Sandstone

Sandstone (SiO2 dominated)

Sandstone (Lithic Sandstone / Greywacke)

Sandstone (SiO2 rich clastic sedimentary rock)

Sandstone Pebble

Sandstone (primarily Quartz, SiO2)