Sedimentary Or Igneous Fragment

Quartz (Milky/Crystalline fragment)

Silicon Dioxide (SiO2)

Milky quartz (likely quartz vein fragment)

Quartz, silicon dioxide (SiO₂)

Banded sandstone

Quartz-rich sandstone (quartz arenite or feldspathic sandstone; exact type cannot be determined from the image)

Banded Gneiss

Gneiss

Gneiss

Gneiss

Raw milky quartz (likely quartz/chalcedony fragment)

Quartz, silicon dioxide (SiO₂)

Weathered granite or granitic rock fragment

Granite; quartz–feldspar–mica aggregate

Weathered quartz-rich rock fragment

Indeterminate; possibly weathered granite, quartzite, or rhyolite

Raw quartz fragment

Quartz (SiO₂), likely milky or included quartz

Garnet-bearing gneiss

Biotite–garnet gneiss, typically quartz + feldspar + biotite + almandine garnet

Rounded quartz pebble (tentative)

Quartz, silicon dioxide (SiO₂)

Likely weathered metamorphic rock (possibly schist or gneiss)

Indeterminate; probable mica-rich quartz–feldspar metamorphic rock

Banded Gneiss Pebble

Gneiss (Metamorphic Rock)

Shale or slate fragment

Fine-grained phyllosilicate rock, likely slate (metamorphosed shale)

Banded Gneiss / Metamorphic River Pebble

Gneiss (Foliated Metamorphic Rock)

Likely fossiliferous limestone fragment

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

Quartz

Silicon Dioxide (SiO2)

Quartz crystal fragment (likely milky quartz)

Quartz, silicon dioxide (SiO₂), trigonal crystal system

Likely raw mica-bearing metamorphic rock or mineral fragment

Tentatively biotite schist; visually similar dark mica-rich material

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Small weathered rock fragment

Unidentified lithic fragment; composition cannot be determined from the image

Vesicular basalt (scoriaceous volcanic rock)

Scoria; iron-rich vesicular basalt, primarily plagioclase, pyroxene, olivine, and volcanic glass

Fossil-bearing fine-grained sedimentary rock

Likely fossiliferous mudstone or shale; visible feature may be a plant fragment, trace fossil, or mineral vein

Chert (likely flint)

Microcrystalline quartz (SiO₂), varieties commonly called chert or flint

Tumbled brecciated jasper

Silica-rich microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions

Weathered sandstone or fine-grained graywacke

Clastic sedimentary rock; chiefly quartz (SiO₂), feldspar, and lithic fragments bound by silica, calcite, or iron-oxide cement

Quartz crystal fragment

Quartz (silicon dioxide, SiO₂)

Biotite-bearing gneiss or schist

Quartz–feldspar–mica metamorphic rock, likely mica schist/gneiss

Milky Quartz Fragment

Silicon Dioxide (SiO2)

Likely quartz-rich stone, possibly milky quartz or chalcedony

Quartz (SiO₂), possibly microcrystalline chalcedony

Quartz Drusy (on Geode Fragment)

Crystalline Silicon Dioxide (SiO2)

Quartz Druze on Matrix (Geode Fragment)

Quartz (Silicon Dioxide, SiO2)

Orange mineral fragment, possibly citrine or iron-stained quartz

Quartz (SiO₂), tentatively iron-included quartz/citrine

Likely garnet crystal

Garnet group, possibly almandine (Fe₃Al₂(SiO₄)₃); identification is uncertain from the photo

Conglomerate

Conglomerate (clastic sedimentary rock)

Granite with a quartz-rich inclusion

Granite, composed mainly of quartz, feldspar, and mica

Weathered granite or granitic gneiss fragment

Quartz–feldspar–mica granite; possibly foliated granitic gneiss

Gravel (Crushed Stone Aggregates)

Mixed Siliciclastic / Carbonate Aggregate

Weathered granite or granitic pegmatite fragment

Granite; chiefly quartz, feldspar, and mica (variable composition)

Quartz Geode

Silicon Dioxide (SiO2) within Sedimentary or Igneous host

Quartz vein in foliated metamorphic rock

Likely quartz-bearing schist or gneiss; visible crystal is quartz (SiO₂)

Generic Pebble / Rock Fragment

Lithic fragment / Weathered rock