Igneous And Metamorphic Derivative (Weathered)

Tumbled dark quartzite or basalt pebble

Likely fine-grained basalt (plagioclase–pyroxene), though quartzite is possible from the image

Likely weathered gneiss

Banded quartz–feldspar–mica gneiss

Strawberry Quartz

Quartz with Hematite inclusions (SiO2 + Fe2O3)

Weathered, iron-stained rock (likely sandstone or breccia)

Indeterminate clastic sedimentary rock; possible ferruginous sandstone or weathered breccia

Likely quartz-rich rock fragment

Indeterminate; probably microcrystalline quartz (SiO₂) with minor feldspar or weathering minerals

Likely biotite-bearing metamorphic rock (schist or gneiss)

Mica schist/gneiss; chiefly quartz, feldspar, and biotite mica

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) in matrix

Weathered quartz-rich pebble

Likely quartzite or felsic granitoid fragment; predominantly SiO₂ quartz with minor feldspar and dark iron-bearing minerals

Likely polished bronzite or serpentine-rich rock

Probable bronzite, an iron-bearing orthopyroxene (Mg,Fe)SiO₃; exact identification requires testing

Likely iron-stained quartz pebble

Quartz (SiO₂), possibly with iron-oxide staining

Fossil shell fragment, likely bivalve or brachiopod

Indeterminate fossilized mollusk/brachiopod; commonly calcite (CaCO₃)

Quartz-rich feldspathic rock, possibly weathered granite or quartzite

Likely quartz and feldspar aggregate; exact identification is uncertain from the photograph

Weathered quartz-rich rock, likely granite or quartzite

Indeterminate; probable quartz–feldspar aggregate, possibly granitic gneiss

Tumbled quartz-rich pebble (likely milky quartz or quartzite)

Quartz, SiO₂; possibly quartzite, a metamorphic quartz aggregate

Milky quartz (likely quartz-rich rock)

Quartz, silicon dioxide (SiO₂)

Quartz Pebble

Silicon Dioxide (SiO2)

Gneiss (Banded Gneiss Cobble)

Gneiss

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Likely milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Quartz-bearing rock fragment

Likely quartz (SiO₂) with iron-oxide staining and possible feldspar/matrix minerals

Likely garnet-bearing metamorphic rock

Garnet amphibolite or garnet-bearing schist; chiefly almandine garnet (Fe₃Al₂Si₃O₁₂) with amphibole, mica, and quartz

Small rounded pebble, likely quartz-rich stone

Indeterminate from photograph; possibly microcrystalline quartz (SiO₂) or a weathered silicate pebble

Small weathered rock fragment

Indeterminate; possibly granitic or altered feldspathic material

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic volcanic rock; commonly basalt (plagioclase, pyroxene, and possible olivine)

Banded gneissic rock

Gneiss, likely quartz–feldspar–biotite gneiss

Green aventurine quartz (probable)

Quartz, SiO₂, with fuchsite or other green mica inclusions

Unidentified translucent mineral fragment, possibly quartz

Likely quartz (SiO₂), though the photograph is insufficient for confident identification

White quartz pebble

Quartz, silicon dioxide (SiO₂), likely milky quartz

Likely milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Iron-rich quartz pebble

Quartz (SiO₂) with iron-oxide staining or inclusions; exact identification is uncertain from the photo

Quartz (Iron-stained or Chalcedony varieties)

Silicon Dioxide (SiO2)

Sapphire

Corundum (Al2O3)

Small quartz-rich rock fragment

Likely quartz-bearing granite, pegmatite, or quartzite; exact identification is uncertain from the photograph

Likely quartz-bearing rock fragment

Quartz (SiO₂), possibly with calcite or feldspar

Quartz pebble

Silicon dioxide (SiO2)

Quartz Pebble (with probable Iron staining)

Silicon Dioxide (SiO2)

Weathered quartz-bearing rock, possibly gneiss or quartzite

Indeterminate; likely quartz-rich metamorphic rock containing quartz and feldspar

Weathered quartz-rich rock, possibly quartzite or granitic pegmatite fragment

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

Milky Quartz (Water-worn pebble/nodule)

Quartz (Silicon Dioxide - SiO2)

Quartz vein in weathered host rock

Quartz (SiO₂), likely in a weathered metamorphic or igneous matrix

Weathered metamorphic rock, likely schist or gneiss

Quartz–feldspar–mica metamorphic rock; exact identification requires testing

Granite Gneiss River Rock

Gneiss