Industrial Byproduct (Anthropogenic Rock)

Sandstone

Quartz Arenite / Clastic Sedimentary Rock

Quartz crystal (likely clear quartz)

Quartz, silicon dioxide (SiO₂)

Quartz-encrusted Matrix

Silicon Dioxide (SiO2) with Ferruginous Sandstone

White Topaz

Aluminum Silicate Fluoride Hydroxide; Al2SiO4(F,OH)2

Sandstone (lithic/quartz variant)

Clastic sedimentary rock (SiO2 predominant)

Basalt

Basalt (Ma-Fe Silicate)

Quartz vein in host rock

Milky quartz (SiO₂) with likely metamorphic country rock, possibly gneiss or schist

Small rounded pebble or stone

Unidentified lithic pebble; composition cannot be determined from the photograph

Peridotite (Olivine/Peridot)

Peridotite (comprising (Mg,Fe)2SiO4)

Greenish metamorphic rock (possibly chlorite schist)

Chlorite-rich schist; exact identification is uncertain from the image

Pegmatite with Quartz and Feldspar

Intrusive Igneous Rock

Small water-worn pebble, likely quartz-rich rock

Undetermined rounded lithic pebble; exact composition cannot be identified from the image

Sandstone

Arenite (Sandstone)

Sandstone

Arenite (specifically Quartz Arenite)

Red-brown pebble, possibly iron-stained sandstone

Indeterminate from the image; likely iron-oxide-stained quartz-rich rock

Agate

Silicon Dioxide (Chalcedony), SiO2

Sandstone with Quartz Vein

Arenite with Crystalline Silica (SiO2)

Rounded river pebble (lithology unclear)

Indeterminate natural rock; no specific mineral or rock type can be identified from the image

Dark gray rock fragment

Indeterminate from image; possibly weathered basalt or fine-grained metamorphic rock

Basalt

Basalt (extrusive igneous rock)

Basalt

Mafic Igneous Rock (Basalt)

Blue tumbled glass-like specimen; likely blue slag glass

Likely man-made glass (silicate glass), not a natural mineral; exact material cannot be confirmed from the image

Clear Quartz / Diamond (untested)

Silicon Dioxide (SiO2) or Carbon (C)

Small brown stone (indeterminate)

Unidentified; the image does not show enough detail for a reliable identification

Coal (Anthracite or Bituminous)

Carbonaceous sedimentary rock (Carbon)

Quartz Geode

Silicon Dioxide (SiO2) within a sedimentary or volcanic shell

Quartzite

Quartzite (principally SiO2)

Pumice

Pumicite (Volcanic glass with vesicular texture)

Pumice

Pumiceous rhyolite

Pink Granite

Granitoid (rich in Potassium Feldspar)

Sandstone Pebble

Arenite (Siliclastic sedimentary rock)

Dalmatian jasper (polished stone beads)

Commercial “Dalmatian jasper”; typically a feldspar-rich rock with dark aegirine or arfvedsonite inclusions, not true jasper

Small water-worn pebble, likely granite or granitic rock

Granite (tentative; exact identification is uncertain from the photo)

Pegmatite or Graphic Granite

Intrusive Igneous Rock

Quartzite with Quartz Veins

Quartzite

Clay Brick

Ceramic structural unit (Al2O3·2SiO2·2H2O as precursor)

Quartz Geode

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Quartzite

Quartzite (SiO2)

Rounded river pebble

Indeterminate lithic clast; likely weathered sandstone or quartz-rich sedimentary rock

Granite

Phaneritic Plutonic Igneous Rock

Conglomerate

Clastic Sedimentary Rock (Conglomerate)