Industrial Byproduct (Anthropogenic Rock)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) in matrix

Quartzite

Quartzite (SiO2)

Vesicular basalt (likely scoria)

Basaltic scoria; predominantly plagioclase, pyroxene, and olivine in a mafic volcanic glass/microcrystalline matrix

Amethyst pendant

Quartz, SiO₂; purple variety known as amethyst

Sandstone (Ferruginous)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 cement)

Sandstone (Ferruginous)

Arenite with Iron Oxides

Greenstone (likely chlorite- or epidote-altered basalt)

Metamorphosed mafic volcanic rock; commonly chlorite–epidote–actinolite assemblage

Quartzite

Quartzite (primarily SiO2)

Bauxite

Aluminum ore (mixture of gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH))

Rounded quartz-rich pebble

Likely vein quartz or quartzite; exact identification is uncertain from the image

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2)

Greenish Metamorphic Rock (likely containing epidote or chlorite)

Metamorphic rock, possibly epidosite or greenstone

Small rough rock fragment, likely iron-rich sedimentary rock or weathered soil-cemented material

Indeterminate from the photograph; possibly ferruginous sandstone or ironstone

Small pale stone (undetermined)

Unidentified geological specimen; image lacks detail for a reliable mineral or rock identification

Quartz Vein in Metamorphic Rock

Silicon Dioxide (SiO2) within Metasedimentary host

Granite Cobble

Phaneritic Felsic Igneous Rock

Gabbro (Water-worn Pebble)

Phaneritic Mafic Igneous Rock

Pink Granite

Intrusive Igneous Rock (Granitic)

Red Shale

Fissile Siliciclastic Sedimentary Rock

Rounded quartz-rich pebble

Likely milky quartz (silicon dioxide, SiO₂); precise identification is uncertain from the image

Coal

Bituminous or Anthracite coal (carbon-rich sedimentary rock)

Pumice

Pumice (Volcanic Rock)

Basalt

Basalt

Basalt

Mafic Igneous Pebble

Granodiorite

Granodiorite (intermediate plutonic rock)

Basalt

Basalt (Mafic volcanic rock)

Basalt

Basalt (Mafic volcanic rock)

Sandstone Pebble

Arenite (SiO2 based)

Quartz vein in metamorphic rock

Crystalline Silicon Dioxide (SiO2) in Host Rock

Basalt

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Serpentine / Antigorite

Mg3Si2O5(OH)4 (Serpentine Group)

Rounded gray pebble (likely fine-grained volcanic or sedimentary rock)

Undetermined from image; possibly andesite or a fine-grained sandstone

Copper Ore

Cupriferous rock mixture (contains Chalcopyrite and Bornite)

Blue-gray mineral specimen (possibly sodalite)

Undetermined; appearance may be consistent with sodalite (Na₈Al₆Si₆O₂₄Cl₂), but the image is insufficient for reliable identification

Rounded river stone (likely iron-stained sandstone or siltstone)

Indeterminate ferruginous sandstone/siltstone; composition cannot be confirmed from the image

Small weathered fossil or mineral fragment

Indeterminate; possibly fossilized shell, bone, or a pale carbonate mineral

Pumice and Scoria

Vesicular Volcanic Ejecta (Rhyolite/Andesite/Basalt)

Quartz-veined weathered host rock

Quartz (SiO₂) in a likely altered limestone or metamorphic carbonate host

Assorted rock and mineral specimens

Multiple unidentified specimens; individual mineral and rock names cannot be determined from this image

Dalmatian jasper (often sold as Dalmatian stone)

Quartz- and feldspar-rich porphyritic volcanic rock; the trade name “Dalmatian jasper” is not a formal mineral species

Quartz–iron-oxide breccia or weathered quartz-bearing rock

Quartz (SiO₂) with limonite/goethite and possibly iron sulfides in a brecciated host

Sandstone

Arenite (SiO2 primarily)