Sedimentary Rock (Possibly Conglomerate Or Breccia With A Quartz Vein)

Rounded dark river cobble, likely basalt

Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, commonly with olivine

Likely quartz-bearing granite or pegmatite fragment

Granite/pegmatite, chiefly quartz (SiO₂) with feldspar and possibly mica

Brecciated jasper

Chalcedony–quartz aggregate, predominantly SiO₂, with iron-oxide coloring

Conglomerate

Polymictic Conglomerate

Pink-and-white quartz-rich rock, likely rose quartz matrix

Quartz (SiO₂), possibly intergrown with feldspar or chalcedony

Weathered quartz-rich rock, possibly quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂)

Likely quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂); if granular and recrystallized, quartzite

Chert Breccia

Brecciated Chert (Microcrystalline SiO2)

Quartz-rich rock, likely milky quartz vein material

Mostly quartz (SiO₂); exact rock type cannot be determined from the image alone

Iron-stained quartz-bearing rock

Quartz (SiO₂), likely with limonite/goethite iron oxides and possibly feldspar

Quartz-bearing dark mineral specimen

Quartz (SiO₂) on a dark host rock, possibly basalt or sulfide-rich ore

Sandstone with Quartz Vein

Arenite with Quartz (SiO2) Infilling

Iron-stained quartz-rich rock, possibly ironstone or quartz-vein material

Quartz (SiO₂) with iron oxides/hydroxides; exact host rock cannot be determined from the image

Quartz-rich translucent fragment

Quartz, silicon dioxide (SiO₂), possibly chalcedony or vein quartz

Quartz Pebble

Silicon dioxide (SiO2)

Quartz Vein in Basalt or Sedimentary Host Rock

Silica-veined lithic fragment (SiO2 in host matrix)

Iron-stained quartz-rich rock, likely quartzite or silicified breccia

Quartz (SiO₂), possibly quartzite with limonite/goethite iron oxides

Conglomerate

Sedimentary Conglomerate

Likely weathered quartz-rich pebble

Quartz (SiO₂), possibly iron-stained quartz or quartzite

Weathered quartz-bearing rock, possibly druzy quartz or quartzite

Quartz (SiO₂), likely in a quartz-rich host rock; exact identification is uncertain from the photograph

Conglomerate

Clastic sedimentary rock (Puddingstone)

Conglomerate

Clastic sedimentary rock (Psephite)

Rounded quartz-rich pebble, likely milky quartz with iron-oxide inclusions

Quartz (SiO₂), possibly with minor chlorite or iron/manganese oxides

Vuggy quartz-rich rock, possibly quartzite or quartz geode

Microcrystalline to crystalline SiO₂ (quartz), likely quartzite with a small quartz-lined vug

Pyrite in Quartz

Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)

Iron-stained quartz-rich rock, possibly quartzite or hydrothermal quartz

Quartz (SiO₂), likely with iron oxides; exact host rock uncertain from the photograph

White chalcedony or quartz-rich pebble

Microcrystalline quartz (SiO₂), possibly with minor calcite or feldspar

Iron-rich breccia or gossan rock

Goethite–hematite–limonite aggregate, possibly with chalcopyrite/malachite staining

Quartz-rich granitic rock, possibly pegmatite

Quartz–feldspar aggregate; likely granite or granitic pegmatite

Quartz-veined Basalt or Diabase Pebble

Igneous rock with hydrothermal quartz vein

Iron-stained quartz-rich rock, possibly smoky quartz

Quartz (SiO₂), likely with iron-oxide staining and dark inclusions; exact identification is uncertain from the photo

Weathered quartz-rich pebble

Quartz (SiO₂), possibly quartzite or quartz-bearing vein rock

Shale with Quartz Vein

Argillaceous Shale with Silicon Dioxide Vein

Weathered quartz-rich rock, possibly gold-bearing quartz

Milky quartz with iron-oxide staining; exact host rock is uncertain from the image

River Pebble (Siltstone / Fine-grained Sandstone)

Sedimentary Pebble (Siliclastic)

Quartz-rich rock, possibly milky quartz with chlorite or epidote

Quartz (SiO₂), with unidentified green inclusions

Quartz Vein in Sedimentary Rock

Silicon Dioxide (SiO2) with host Chert or Limestone

Quartz Pebble

Silicon Dioxide (SiO2)

Weathered quartz-rich rock, likely milky quartz with iron staining

Quartz (SiO₂), possibly quartz vein material or quartzite

Likely quartz-rich rock fragment

Quartz (SiO₂), possibly in a feldspar-bearing granite or pegmatite matrix

Likely small quartz pebble

Quartz (SiO₂), possibly a weathered quartz-rich rock fragment

Siltstone with Quartz Vein

Siltstone (composed of Quartz and Clay minerals) with a hydrothermal Quartz vein (SiO2)