Mineral, Possibly Rock Fragment Containing A Mineral

Sandstone

Arenite

Sandstone (with possibly iron oxides and other minerals)

Sandstone

Sandstone (Quartzose)

Arenite (primarily SiO2)

Granite with Cupules / Bedrock Mortars

Granite (felsic intrusive plutonic rock)

Likely weathered quartz-rich rock, possibly smoky quartz or chert

Quartz (SiO₂), though exact identification is uncertain from the photograph

Sandstone (Greywacke/Lithic Sandstone)

Clastic Sedimentary Rock (Lithic Sandstone)

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Red Sandstone

Arenite (primarily Quartz with Hematite cement)

Iron-stained quartz-rich rock, possibly jasper/quartzite

Quartz (SiO₂) with iron-oxide staining; likely ferruginous quartzite or jasper

Sandstone

Arenite (SiO2 principal)

Quartz Geode (likely within Limestone or Dolomite matrix)

Quartz (SiO₂)

Red Sandstone

Arenite (with iron oxide cement)

Iron-stained quartz-rich rock, possibly weathered granite or pegmatite

Quartz (SiO₂) with probable feldspar and iron-oxide staining; exact identification is uncertain from the photograph

Weathered quartz-rich rock, possibly granite or pegmatite fragment

Uncertain; likely quartz–feldspar aggregate, potentially granitic pegmatite

Weathered green-gray stone, likely serpentinite or chlorite-rich metamorphic rock

Probable serpentinite (antigorite–lizardite), possibly chlorite schist or altered basalt

Sandstone

Arenite (SiO2 based)

Unidentified translucent mineral fragment, possibly calcite

Calcite (calcium carbonate, CaCO₃), tentative identification

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Polished agate geode

Chalcedony (microcrystalline quartz, SiO₂) with quartz druse crystals

Asphalt Concrete

Bituminous Concrete (Anthropic Rock)

Porphyritic Basalt or Lamprophyre

Extrusive igneous rock with visible phenocrysts

Sandstone

Arenite (SiO2 based)

Quartz-bearing iron-rich rock, possibly quartzite or hydrothermal breccia

Quartz (SiO₂) with iron oxides/hydroxides, likely limonite/goethite; exact host rock is uncertain from the photograph

Sandstone

Arenite (Clastic Sedimentary Rock)

Weathered limestone

Calcite-rich carbonate rock (mostly CaCO₃), possibly fossiliferous limestone

Amber

Succinite (fossilized tree resin)

Greywacke (River Pebble with Quartz Veins)

Greywacke (Indurated Sandstone); Veins: SiO2 (Quartz)

Sandstone

Arenite (predominantly SiO2)

Fossiliferous Sandstone / Mudstone

Sedimentary Rock (Clastic with Fossiliferous Inclusions)

River Pebble

Polished Rock Fragment

Probable amber fragment

Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)

Basalt and weathered granite-like rock

Dark specimen: basalt, likely vesicular or fine-grained mafic volcanic rock; tan specimen: uncertain, possibly weathered granite or iron-stained felsic rock

Ocean Jasper

Orbicular Jasper / Silicate

Note regarding baguette production (not a rock)

Digital text image - Somali language

Sandstone (with Iron Staining)

Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 oxides)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Ironstone (likely siderite or goethite-rich siltstone)

Ferruginous Siltstone

Mica Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

Sandstone (with Lichen)

Arenite (primarily SiO2)

Likely hematite-rich ironstone or metallic mineral fragment

Hematite (Fe₂O₃), possibly with magnetite (Fe₃O₄) or metallic iron

Granite Sand (Decomposed Granite)

Grus / Quartz-Feldspar Detritus

Sandstone

Arenite (predominantly Quartz Sandstone)