Rock (Likely Sedimentary)

Artificial Rock Face (Faux Rock)

Glass Fiber Reinforced Concrete (GFRC)

Mixed rock and mineral gravel

Predominantly granite/granodiorite, basaltic rocks, quartz, and possible gneiss; exact identification is uncertain from the image

Fluorite (likely Green Fluorite variant)

Calcium Fluoride (CaF2)

River Cobble (likely Quartzite or Limestone)

SiO2 (Quartzite dominant) or CaCO3 (Limestone dominant)

Small pale mineral fragment

Unidentified; possibly quartz, calcite, or feldspar

Basalt with Sulfide/Pyrite inclusion

Aphanitic Mafic Igneous Rock (likely Basalt) with Pyrite (FeS2)

White quartz geode

Quartz, silicon dioxide (SiO₂), likely a druzy quartz geode

Tumbled pale greenish stone, likely serpentine or altered limestone

Probable serpentine-group rock (antigorite/lizardite), possibly serpentinite; identification is visual only

Garnet (Almandine/Pyrope series)

Garnet Group - X3Y2(SiO4)3

Quartz Pebble

Silicon Dioxide (SiO2)

Dark mafic rock, likely basalt

Basalt; chiefly plagioclase feldspar, clinopyroxene, and commonly olivine or iron oxides

Banded Calcite (often sold as 'Mexican Onyx')

Calcite (Calcium Carbonate, CaCO3)

Polished/tumbled quartz-rich pebble, possibly jasper or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂), potentially iron-stained jasper or quartzite

Quartz-bearing granite or gneiss fragment

Granite/gneiss composed mainly of quartz (SiO₂), feldspar, and minor mica or ferromagnesian minerals

Orange chalcedony or weathered quartz pebble

Microcrystalline quartz, SiO₂; possibly iron-oxide-stained chalcedony

Glacial Quartzite Cobble

Meta-orthoquartzite (SiO2)

Serpentinite (likely)

Serpentinite, dominated by serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and minor chlorite/talc

Micaceous Rock (likely Muscovite Schist/Gneiss or a Muscovite-rich Specimen)

Predominantly Muscovite (KAl2(AlSi3O10)(F,OH)2), often found in rocks like Muscovite Schist or Muscovite Gneiss.

Banded Gneiss with Quartz Veining

Gneiss (High-grade Regional Metamorphism)

Weathered granitic rock, likely granodiorite

Granodiorite: quartz, plagioclase feldspar, potassium feldspar, and biotite/hornblende

Quartz-rich sandstone or granitic fragment

Likely quartz–feldspar sandstone; exact identification is uncertain from the photograph

Chalcedony (Common Agate pebble)

Silicon Dioxide (SiO2)

Chalcedony (Yellow Agate/Chert)

Silicon Dioxide (SiO2)

Rounded gray river cobble

Likely basalt or fine-grained mafic volcanic rock; exact identification requires testing

Chalcedony (Agate Pebble)

Silicon Dioxide (SiO2)

Chalcedony Pebble

Cryptocrystalline Quartz (SiO2)

Sandstone

Arenite (a specific type of sandstone with less than 15% matrix)

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Drupa Quartz (Sparkly Drusy Quartz on Matrix)

Crystalline Silicon Dioxide (SiO2) on host rock

Quartz (Tumbled/Water-worn)

Silicon Dioxide (SiO2)

Limestone (with possible Manganese oxide inclusions)

Sedimentary Calcium Carbonate (CaCO3)

Polished brecciated jasper (likely septarian or iron-rich jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and possibly calcite or other rock fragments

Man-made Synthetic Material (Plastic/Composite)

Acrylonitrile Butadiene Styrene (ABS) or High-Impact Polystyrene (HIPS)

Likely basaltic rock fragment

Fine-grained mafic igneous rock, probably basalt (plagioclase–pyroxene ± olivine)

Granite

Intrusive igneous rock (high SiO2)

Quartz (likely a macrocrystalline variety like milky quartz or smoky quartz, given the appearance in the image)

Quartz (SiO₂ - Silicon Dioxide)

Weathered quartz-bearing sandstone

Quartz arenite or feldspathic sandstone (tentative)

Fossiliferous Limestone with Brachiopods

Calcium Carbonate (CaCO3) with fossilized Brachiopoda sp. (likely Order Spiriferida or Rhynchonellida)

Weathered quartz-rich rock fragment

Likely quartz-bearing feldspathic rock; exact identification requires testing

Weathered limestone or calcareous sandstone

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

Granite Pebble

Granite (composed mainly of Quartz, Feldspar, and Mica)

Basalt

Basalt (Mafic volcanic rock)