Industrial Byproduct (Anthropogenic Rock)

Quartzite River Stone

Quartzite (SiO2)

Kimberlite

Kimberlite

Iron-stained quartz-rich rock (possibly ironstone)

Quartz (SiO₂) with iron-oxide/hydroxide staining, likely limonite/goethite

Coal

Combustible Sedimentary Rock

Calcite Vein in Limestone

Calcium Carbonate (CaCO3)

Mineral Specimen Collection (Galena, Quartz, Calcite, Hematite, etc.)

Mixed Mineral Assemblage (PbS, SiO2, CaCO3, Fe2O3, ZnS, etc.)

Likely polished or naturally smoothed pebble with a pale mineral patch

Undetermined; possibly a dark volcanic rock with a quartz or feldspar inclusion

Small pale stone (unidentified)

Undetermined; image detail is insufficient for reliable identification

Small rounded pebble; specific identification uncertain

Indeterminate lithic fragment; mineral composition cannot be determined from the image

Shale

Shale (claystone/mudstone)

Vesicular Basalt (Lava Rock)

Basalt

Quartz-rich geode or mineralized cavity in host rock

Likely a quartz-bearing geode; the pale crystals may be quartz (SiO₂), but the photo is not detailed enough for a firm identification.

Quartz Pebble (Iron-Stained)

Crystalline Silicon Dioxide (SiO2)

Vesicular Basalt

Extrusive Mafic Igneous Rock (Vesicular Basalt)

Coal (Bituminous Coal)

Caustobiolith / Sedimentary Rock

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Garnet Schist

Garnetiferous Micaceous Schist

Small tan mineral or rock fragment (unidentified)

Indeterminate from the image; no diagnostic features are visible

Unidentified rock fragments

Indeterminate; likely a weathered, iron-stained silicate rock

Blue-gray stone pebble (possibly slag or a weathered rock)

Unidentified fine-grained rock; composition cannot be determined from the image

Coal

Biogenic sedimentary rock (Carbon)

Slate

Foliated Metamorphic Rock

Weathered river pebble (likely iron-stained rock)

Indeterminate from the image; possibly iron-oxide-stained quartzite or sandstone

Rounded gray-brown pebble

Indeterminate; likely weathered quartz-rich sandstone or fine-grained volcanic rock

Quartz and Iron Oxide

Quartz (Silicon Dioxide, SiO2) with possible Limonite/Hematite inclusions

Limestone Cobble

Carbonate Rock (CaCO3)

Quartz Geode

Silicon Dioxide (SiO2)

Agate

Silicon Dioxide (Chalcedony), SiO2

Biotite-rich mica schist

Mica schist, likely containing biotite and quartz with possible feldspar

Copper Ore

Chalcopyrite in host rock (CuFeS2)

Iron-stained rock, likely limonite-rich weathered stone

Limonite (iron oxyhydroxides, chiefly goethite) coating or staining a rock of uncertain composition

Rounded pebble, likely fine-grained river stone

Unidentified lithic pebble; composition cannot be determined from the image

Coal

Combustible Sedimentary Rock

Small pale stone fragment (undetermined)

Unidentified; the image lacks diagnostic detail for a reliable identification

Possible iron-rich pebble with a weathered inclusion

Unidentified; image alone does not support a reliable mineral or rock identification

Pyrite

Iron Sulfide (FeS2)

Small dark rock fragment (not identifiable from the image)

Undetermined; no diagnostic mineral features are visible

Pink Sapphire

Corundum (Al2O3)

Green glassy slag (often sold as “sea glass” or “green obsidian”)

Industrial vitreous slag; primarily amorphous silicate glass, composition variable

Small dark rock fragment, possibly shale or slate

Undetermined fine-grained silicate rock; visual identification is inconclusive

Porphyritic Andesite

Andesite (Intermediate Volcanic Rock)

Likely sodalite (rough blue specimen)

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂