Mixed (Predominantly Sedimentary And Igneous)

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous

Sandstone

Arenite (predominantly SiO2)

Sodalite

Sodalite: Na8(Al6Si6O24)Cl2

Tumbled brown chalcedony or jasper

Microcrystalline quartz, SiO₂; likely iron-oxide-bearing chalcedony/jasper

Anthracite coal

Anthracite; predominantly carbon (C), with minor mineral impurities

Granite

Granite (Phaneritic Igneous Rock)

Fluorite

Calcium Fluoride (CaF2)

Pumice

Vesicular volcanic glass (Amorphous silica mixed with various oxides)

Sandstone

Arenite (predominantly SiO2)

Sandstone

Arenite (SiO2 predominantly)

Sandstone River Pebble

Arenite (SiO2 predominantly)

Sandstone

Arenite (SiO2 predominantly)

Amazonite

Microcline (variety Amazonite), K(AlSi3O8)

Banded Gneiss

Gneiss (Metamorphic rock predominantly containing quartz, feldspar, and mica)

Possible tumbled jasper or iron-rich chert

Microcrystalline quartz (SiO₂), variably mixed with iron oxides

Mixed Gemstone Collection

SiO2 (Quartz varieties) and Biogenic CaCO3 (Nacre)

Chrysanthemum Stone

Limestone with Celestite or Andalusite inclusions

Mixed beach pebbles and shell fragments

Mostly carbonate rocks, likely limestone/calcarenite, with mollusk-shell bioclasts; exact species cannot be determined visually

Alluvial stream gravel (mixed rock specimens)

Polymictic fluvial deposit; likely mixtures of quartzite, sandstone, shale, chert, basalt, and granite-derived minerals

Mixed river pebbles and quartz-rich specimens

Polymictic fluvial gravel; likely quartz, quartzite, chert, and weathered feldspathic rocks

Yellow Quartz (Citrine or Citrine-colored Quartz)

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 predominantly)

Anthracite Coal

Coal (predominantly carbon)

Sandstone River Cobble

Arenite (predominantly SiO2)

Sandstone (Quartzose)

Arenite (predominantly SiO2)

Colorless faceted gemstone, likely cubic zirconia

Synthetic cubic zirconia (zirconium dioxide, ZrO₂); identity is visual and not definitive

Granite

Intrusive Igneous Rock

Likely tumbled hematite-rich ironstone

Hematite, Fe₂O₃, possibly mixed with goethite or magnetite

Botryoidal hematite (iron-oxide specimen)

Hematite, Fe₂O₃; possibly mixed with goethite/limonite

Mixed rounded gravel and pebbles

Polymictic clasts, likely including granite, basalt, quartzite, sandstone, and schist

Quartz-rich rock fragments, likely granite or gneiss

Granite/gneiss assemblage; chiefly quartz (SiO₂), feldspar, and mica

Limonite

FeO(OH)·n(H2O)

Mixed tumbled river pebbles and beach stones

Polymictic alluvial gravel; components include quartz, chert, jasper, sandstone, and altered volcanic rocks

Mixed River Pebbles (Jasper, Hematite, and Quartzites)

Silicon dioxide (Jasper/Quartz) and Iron oxide (Hematite)

Granite

Intrusive Igneous Rock

Flint

SiO2 (Cryptocrystalline Quartz)

Botryoidal hematite (ironstone)

Hematite, Fe₂O₃; likely a botryoidal or massive iron-oxide specimen

Sodalite

Sodium Aluminum Silicate Chloride (Na8(Al6Si6O24)Cl2)

Mixed rounded fieldstones, likely granite and gneiss

Granite (quartz–feldspar–mica) and gneiss; exact identification is uncertain from the photograph

Assorted gemstone jewelry

Mixed natural and synthetic gemstone cabochons and faceted stones; individual species cannot be determined reliably from this image

Fossil Shark Tooth

Carcharocles (Otodus) sp. or similar fossilized Chondrichthyes tooth

Tumbled fossiliferous limestone

Micritic limestone, likely bioclastic/fossiliferous carbonate rock (predominantly CaCO₃)