Igneous And Metamorphic Derivative (Weathered)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Quartz with Iron Oxide Staining

Silicon Dioxide (SiO2)

Quartz-rich feldspathic pebble, possibly granite or granitic gneiss

Quartz–feldspar aggregate, likely granite; dark inclusion may be biotite, hornblende, or iron-oxide staining

Strawberry Quartz

Quartz with Hematite inclusions (SiO2 + Fe2O3)

Weathered quartz-rich rock, possibly pegmatite or quartzite

Quartz (SiO₂)-rich aggregate; exact identification is uncertain from the photograph

Basalt (Stream-worn Cobble)

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Iron-stained quartz-rich rock, possibly gold-bearing quartz

Quartz (SiO₂) with iron-oxide staining; possible limonite/goethite matrix

Mixed Quartz and River Pebbles (Stone Collection)

Mixed assortment containing mainly Silicon Dioxide (SiO2)

Quartz (Milky/Crystalline fragment)

Silicon Dioxide (SiO2)

Magnetite / Hematite (Iron Ore Pebble)

Fe3O4 (Magnetite) / Fe2O3 (Hematite)

Phyllite (possibly low-grade greenish slate)

Foliated metamorphic rock composed mainly of very fine-grained quartz, mica, and chlorite; approximate composition varies and has no single fixed chemical formula

Small quartz-rich rock fragment (tentative)

Quartz, silicon dioxide (SiO₂), possibly in a feldspar-bearing granite fragment

Garnet

Almandine (Fe3Al2(SiO4)3)

Weathered quartz-rich pebble

Milky quartz, chiefly silicon dioxide (SiO₂), possibly with iron-oxide staining and minor feldspar

Milky quartz (likely weathered quartzite or quartz vein fragment)

Quartz, silicon dioxide (SiO₂)

Weathered granite (likely with accessory quartz)

Granite; chiefly quartz, K-feldspar, plagioclase, and biotite/hornblende

Quartz pebble

Silicon dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Milky quartz (rough quartz specimen)

Quartz, silicon dioxide (SiO₂)

Gneiss (Metamorphic Cobble)

Gneiss

Chalcopyrite

Chalcopyrite (CuFeS2)

Granite with Epidote

Granite, containing quartz, feldspar, and epidote

Quartz-rich pegmatite (possibly quartz–feldspar rock)

Granite pegmatite; chiefly quartz (SiO₂) with feldspar and minor mica/iron staining

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz with Mica (likely Muscovite)

Silicon Dioxide (SiO2) with Potassium Aluminum Silicate Hydroxide Fluoride

White quartz-rich pebble

Likely quartzite or milky-quartz pebble (SiO₂)

Feldspar (Plagioclase / Potassium Feldspar)

Feldspar Group (KAlSi3O8 - NaAlSi3O8 - CaAl2Si2O8)

Gneiss (specifically a weathered or stream-worn specimen)

Gneiss (Foliated Metamorphic Rock)

Quartz Pebble

Silicon Dioxide (SiO2)

Unidentified Rock Fragment

Unknown

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz-rich mineral fragment

Quartz (silicon dioxide, SiO₂), possibly milky quartz

Quartz (Water-worn pebble)

Silicon Dioxide (SiO2)

Sapphire

Corundum (Al2O3)

White Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if the grains are fused

Aventurine (likely Green Aventurine)

Silicon Dioxide (SiO2) with mineral inclusions

Gravel / Crushed Stone

Aggregate (mixed mineral rock fragments)

Quartz pebble

Silicon dioxide (SiO2)

Mossy Rock

Mixed lithology rock with Bryophyta (moss)

Gneiss

Gneiss (Foliated Metamorphic Rock)