Synthetic (Not A Natural Rock)

River Quartzite or Chert Pebble

Quartzite (primarily Silicon Dioxide - SiO2)

Herkimer Diamond

Double-Terminated Quartz (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Corundum (Sapphire in Host Rock)

Corundum (Aluminum Oxide, Al2O3)

Unknown Organic Object (likely a berry or fruit)

Not applicable; this is not a geological specimen. If it were a cranberry, its scientific name would be Vaccinium macrocarpon; if a cherry, it would be Prunus avium or Prunus cerasus.

Tumbled jasper, likely red/brown jasper

Microcrystalline quartz (chalcedony), SiO₂, colored by iron oxides

Red Sandstone

Arenite (with Iron Oxide)

Smoky Quartz

SiO2 (Silicon Dioxide)

Unakite-like granite with a white feldspar inclusion

Granite, chiefly quartz–feldspar–biotite; pale inclusion likely albite/orthoclase feldspar

Granite

Phaneritic plutonic rock (primarily Quartz, Alkali Feldspar, and Plagioclase)

Weathered quartz-rich rock, possibly pegmatite or quartzite

Quartz (SiO₂)-rich aggregate; exact identification is uncertain from the photograph

Ironstone Concretion / Goethite Nodules

Ironstone (composed primarily of Goethite FeO(OH) and Limonite)

Basalt River Cobble

Basalt (Aphanitic Mafic Volcanic Rock)

Sandstone (Weathered Coastal Boulder)

Arenite (composed primarily of SiO2)

Turquoise

Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

Granite

Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Tumbled quartzite pebble

Quartzite; predominantly microcrystalline quartz (SiO₂)

Polished red jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Dyed Blue Agate

Silicon Dioxide (SiO2)

Amethyst-rich vesicular volcanic rock (probable amethyst basalt/scoria)

Quartz (SiO₂) in vesicular basaltic volcanic rock; precise identification requires testing

Weathered quartz-rich rock, possibly sandstone or quartzite

Indeterminate; likely quartz sandstone (SiO₂-rich), possibly weakly metamorphosed quartzite

Red Sandstone

Arenite (predominantly SiO2 with Fe2O3 staining)

Golden Healer Quartz

Ferruginous Quartz (SiO2 with Fe2O3 inclusions)

Weathered granite-like rock

Granite, likely biotite-bearing; exact identification is uncertain from the image

Glauconitic Sandstone (Greensand)

Glauconitic Sandstone ((K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2)

Blue Lace Agate

Silicon Dioxide (SiO2)

Citrine (Heat-Treated Amethyst)

Silicon Dioxide (SiO2)

Red Sandstone

Sandstone (lithic arenite / ferruginous sandstone)

Cullet Glass (Strawberry Glass)

Amorphous Silicon Dioxide (SiO2) with metallic dopants

Sandstone (Ferruginous)

Arenite with Iron Oxide cement

Shale with Plant Fossils / Carbonaceous Shale

Laminated Mudrock (Siliciclastic)

Turquoise in Matrix

Hydrated phosphate of copper and aluminum (CuAl6(PO4)4(OH)8·4H2O)

Sandstone (Yellow/Tan)

Clastic sedimentary rock (primarily SiO2 with iron oxide staining)

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic volcanic rock; commonly basalt (plagioclase, pyroxene, ± olivine)

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

Granite

Granite (Phaneritic Quartz-Feldspar Plutonic Rock)

Shale (with minor calcite veining)

Clastic sedimentary rock (primarily clay minerals and quartz)

Slate

Metamorphosed Shale (Fine-grained Foliated Metamorphic Rock)

Fossilized tooth, likely mammalian molar

Indeterminate Mammalia; mineralized dentine and enamel

Weathered metallic-looking rock, possibly hematite-bearing ironstone

Hematite-rich ironstone; hematite Fe₂O₃, potentially with magnetite Fe₃O₄ and quartz

Hag Stone

Perforated Sedimentary Rock (typically Limestone or Sandstone)