Sedimentary (Microcrystalline Silicate)

Raw pink chalcedony (likely pink agate/jasper)

Microcrystalline quartz, SiO₂ (chalcedony); impurities may include iron oxides and other silicates

Clay (as a rock-forming material)

Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)

Rounded gray pebble

Indeterminate; likely fine-grained quartz-rich silicate rock

Iron Slag

Ferrous slag (primarily silicates and oxides of calcium, iron, and magnesium)

Small tumbled stone, likely quartz-rich pebble

Probably microcrystalline quartz (SiO₂), but the image is insufficient for a definitive identification

Mixed River Stones and Agates

Mixed Silicates and Ironstones (primarily SiO2 and Fe2O3)

Siltstone with Concretion

Siltstone (composed of hydraulic silicates and quartz particles)

Banded Jasper (Mookaite / Chert)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Serpentinite

Serpentinite (complex silicate mineral group (Mg,Fe)3Si2O5(OH)4)

Carnelian / Agate

Silicon Dioxide (SiO2) - Chalcedony variety

Banded Calcite (often sold as 'Mexican Onyx' or 'Calcite Onyx')

Calcite (Calcium Carbonate, CaCO3)

Fossiliferous Sandstone / Quartzite Pebble

Sedimentary rock with skeletal fragments (e.g., Paleozoic crinoid/brachiopod fossils)

Banded Chert

Silicon Dioxide (SiO2)

Green Banded Chert (Agate/Jasper)

Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite

Chert / Flint

Microcrystalline Quartz (SiO2)

Banded gneiss

Foliated silicate rock, typically quartz–feldspar–mica gneiss

Chert

Microcrystalline or cryptocrystalline quartz

Polished orbicular jasper / brecciated jasper bead bracelet

Jasper, microcrystalline quartz (SiO₂), with variable iron oxides and other silicate inclusions

Small rounded pebble, likely quartz-rich stone

Indeterminate from photograph; possibly microcrystalline quartz (SiO₂) or a weathered silicate pebble

Coprolite

Fossilized Feces

Weathered iron-rich rock, possibly laterite or ironstone

Goethite–hematite-rich ferruginous rock; uncertain without testing

Purple Chalcedony

Silicon Dioxide (SiO2)

Mixed Tumbled Rocks and Minerals Collection

Mixed Minerals and Rocks (Quartz, Feldspar, Jasper, Agate, Lapis Lazuli, Sodalite, Rose Quartz, Fluorite, etc.)

Unidentified weathered rock fragment

Likely limestone or sandstone; exact identification is not possible from the photograph

Anthracite Coal

Anthracite

Likely weathered jasper or iron-rich chert

Microcrystalline quartz (SiO₂), with iron-oxide staining

Pyrite-bearing schist or quartzite

Micaceous quartz-rich metamorphic rock with pyrite (FeS₂)

Common Opal (Green Opal / Pistachio Opal)

Hydrated silica (SiO2·nH2O)

White-veined gray limestone or marble

Calcite-rich carbonate rock; likely calcitic marble (CaCO₃)

Jasper

Microcrystalline Quartz (SiO2)

Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

Chrysocolla

Hydrated copper silicates (Cu,Al)2H2Si2O5(OH)4·nH2O

Jasper

Microcrystalline Quartz (SiO2)

Reddish-brown tumbled stone, possibly jasper

Unidentified iron-oxide-stained silicate; exact material cannot be determined from the image

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

Brick

Fired clay or Ceramic material (no specific mineralogical scientific name as it's a composite)

Turquoise

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

Mica Schist

Mica Schist (predominantly Muscovite or Biotite sheet silicates)

Chert (Jasper / Flint variant)

Microcrystalline Quartz (SiO2)

Red Jasper and Hematite

Silicon Dioxide (SiO2) and Iron Oxide (Fe2O3)

Jasper (Iron-rich)

Silicon Dioxide (SiO2) with Fe2O3 (Hematite) impurities

Uncertain dark metamorphic rock, likely schist or slate

Foliated silicate rock; possibly chlorite–mica schist or slate