Metamorphic Or Sedimentary (With Staining)

Ferruginous Quartz on Ironstone

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Quartzite

Quartzite (chiefly SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Agate

Silicon Dioxide (Chalcedony), SiO2

Gneiss

Metamorphic rock of high-grade regional metamorphism

Ferruginous Quartzite (Chert)

Quartzite with Iron inclusions (SiO2 + Fe2O3)

Quartz pebble with a conchoidal chip

Silicon dioxide (SiO2)

Almandine Garnet (weathered)

Almandine (Fe3Al2(SiO4)3)

Weathered quartz-rich pebble (tentative)

Likely quartz/chalcedony, SiO₂, possibly iron-stained

Weathered quartz-rich rock, likely milky quartz or quartzite

Quartz (SiO₂), possibly quartzite with iron-oxide staining

Slate

Foliated Metamorphic Rock (composed primarily of Quartz, Muscovite, and Illite)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (Iron-stained or Chalcedony varieties)

Silicon Dioxide (SiO2)

Agate

Silicon Dioxide (Chalcedony), SiO2

Gneiss Pebble

Gneiss (High-grade metamorphic rock)

Quartz

Silicon dioxide (SiO2)

Iron-rich quartzite or ironstone fragment

Quartzite dominated by quartz (SiO₂), with iron oxides such as hematite/goethite

Greenschist

Greenschist (composed mainly of chlorite, epidote, actinolite, and albite)

Iron-rich quartzite or weathered ironstone

Quartzite, predominantly SiO₂, with limonite/goethite (FeO(OH)·nH₂O) staining

Gneiss (with Quartzite and Biotite)

Gneiss containing SiO2 (Quartz), K(Mg,Fe)3AlSi3O10(OH)2 (Biotite), and (K,Na,Ca)AlSi3O8 (Feldspar)

Milky Quartz (Vein Quartz)

Silicon Dioxide (SiO2)

Gneiss with Iron Staining and Sulfide Mineralization

Metamorphic Gneiss / Amphibolite with Iron/Sulfide Oxidation

Feldspar-rich Quartzite

Metamorphic Quartz-Feldspar Aggregate (SiO2 + KAlSi3O8)

Quartz pebble

Silicon dioxide (SiO2)

Quartz-rich river pebble, likely milky quartz

Milky quartz (SiO₂), possibly a quartzite or quartz-rich silicate pebble

Quartz

Silicon Dioxide (SiO2)

Likely weathered quartz-bearing rock (uncertain identification)

Possibly quartz-rich granite or granitic aplite; exact identification requires a clearer, larger image and tests

Quartz (Raw / Unpolished)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Agate

Silicon Dioxide (Chalcedony), SiO2

Limestone with Iron Oxide Staining

Sedimentary Rock (Calcite, CaCO3)

Quartz

Silicon Dioxide (SiO2)

Dragon Blood Jasper

Epidote and Pietersite-rich Quartz (SiO2 with inclusions)

Quartzite River Rock

Quartzite ($SiO_2$)

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Calcite

Calcium Carbonate (CaCO3)

Gneiss with Quartz Veining

Gneiss (High-grade Metamorphic Rock)

Quartzite River Cobble

Quartzite (primarily SiO2)

Quartzite with Iron Inclusions

Metamorphosed Quartz Arenite (SiO2)

Quartz pebble

Silicon dioxide (SiO2)