Mineral, Possibly Rock Fragment Containing A Mineral

Quartz Geode (Amethyst / Clear Quartz)

Silicon Dioxide (SiO2)

Fossil-bearing sedimentary rock, possibly fossil wood or bone

Indeterminate silicified/carbonate fossil in sandstone or mudstone

Quartz Geode

Silicon Dioxide (SiO2)

Fossiliferous Shale

Laminated Mudrock with plant fossils

Red Sandstone

Arenite (ferruginous sandstone)

Sandstone (Ferruginous)

Arenite with Iron Oxide (Limonite/Hematite) coating

Shale

Argillaceous sedimentary rock

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Granite or Pegmatite in host rock

Granitoid / Felsic Intrusive Rock

Sandstone (specifically Flagstone)

Arenite (primarily composed of SiO2)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Sandstone (Ferruginous)

Clastic Sedimentary Rock (SiO2 with FeO/Fe2O3)

Weathered sandstone or iron-stained sedimentary rock

Quartz-rich sandstone, possibly ferruginous sandstone

Bauxite

Bauxite (principal ore of aluminum, primarily Al(OH)3)

Basalt (Vesicular/Weathered)

Mafic Igneous Rock (Mainly Plagioclase and Pyroxene)

Shale with Coprolite influence

Argillaceous sedimentary rock (Shale/Mudstone)

Gravel / Crushed Stone

Aggregate (mixed mineral rock fragments)

Quartz Geode

Crystalline Silicon Dioxide (SiO2)

Weathered fossiliferous limestone fragment, possibly fossil coral or shell material

Indeterminate carbonate fossil in calcitic limestone; likely composed mainly of calcite (CaCO₃), but species identification is not possible from this image alone

Granite

Intrusive Igneous Rock

Granite

Intrusive Igneous Rock

Quartz Druze on Matrix (Geode Fragment)

Quartz (Silicon Dioxide, SiO2)

Tiger Iron

Tiger Iron (Composition: SiO2, Fe2O3, Fe3O4)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Quartz Fragment

Silicon Dioxide (SiO2)

Porphyry

Porphyritic Igneous Rock

Shale

Fissile mudrock (composed primarily of clay minerals and quartz)

Chalcedony (Agate/Quartz)

Silicon Dioxide (SiO2)

Desert Rose (Barite Rose or Gypsum Rose)

Barium Sulfate (BaSO4) / Hydrated Calcium Sulfate (CaSO4·2H2O)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Granite Gneiss

Gneiss (derived from granitic protolith)

Quartz

Silicon Dioxide (SiO2)

River Pebble

Weathered Sedimentary Rock Fragment

Copper slag or vesicular basalt with copper minerals

Industrial slag / Basaltic matrix with secondary copper minerals

Concretion or Geode (unbroken)

Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.

Sandstone

Arenite (Secondary classification based on grain size)

Flint or chert

Microcrystalline quartz (SiO₂), commonly with chalcedony

Shale

Shale (Lutite)

Mixed river-worn rock and mineral collection

Mostly quartz/quartzite, feldspar-bearing granitoid, chert, and mafic volcanic rocks; exact species vary by pebble

Quartz-veined Granite or Gneiss Pebble

Silicate-rich metamorphic rock fragment

Rounded river pebble

Indeterminate; likely quartz-rich sandstone, chert, or weathered volcanic rock

Shale

Lutaceous sedimentary rock