Rock (Likely Sedimentary)

Chert (or Flint)

Chert (Sedimentary Cryptocrystalline Sio2)

Polished fossiliferous limestone, likely crinoidal or coral limestone

Calcite (CaCO₃), fossiliferous carbonate rock

Weathered metallic-looking rock, possibly hematite-bearing ironstone

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

Sandstone (likely Quartzose Sandstone pebble)

Arenite (primarily SiO2)

Sandstone (likely Arkose or Quartz Sandstone)

Arenite (SiO2 principal component)

Chrysocolla on Matrix

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

Blue-gray quartz-bearing metamorphic rock (likely gneiss or schist)

Quartz–feldspar–mica rock; exact identification requires testing

Gneiss (Metamorphosed Pebble)

Gneiss with Quartz/Feldspar banding

Sandstone (likely Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Graywacke

Graywacke Sandstone

Banded calcite (likely marble or calcite-rich limestone)

Calcite, CaCO₃; possibly calcitic marble

Vesicular basalt (likely weathered lava rock)

Basalt; fine-grained mafic volcanic rock composed chiefly of plagioclase, pyroxene, and commonly olivine

Sandstone with Quartz Vein

Arenite with Quartz (SiO2) protrusion

River Stone (River Pebble)

Stream-rounded clast (likely Quartzite or Siltstone)

Weathered quartz-rich rock, likely milky quartz or quartzite

Quartz (SiO₂), possibly quartzite with iron-oxide staining

Sandstone (likely Red/Brown Sandstone)

Arenite (SiO2 based)

Quartz–mica metamorphic rock, likely schist

Quartz–muscovite/biotite schist; predominantly SiO₂ quartz with phyllosilicate micas

Jasper / Chert (River Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Honey Chert or Chalcedony Pebble)

Cryptocrystalline Quartz (SiO2)

Sandstone (likely Graywacke or Lithic Arenite)

Clastic sedimentary rock predominantly composed of silicate grains

Chert (Grey-Green Var.)

Silicon Dioxide (SiO2)

Porphyritic Basalt (likely artificially dyed or altered)

Basalt with plagioclase phenocrysts (likely treated)

Granite (likely biotite granite or granodiorite)

Coarse-grained granitoid composed mainly of quartz, feldspar, and dark biotite/hornblende

Graphite-rich schist (likely graphite ore)

Graphite-bearing schist; predominantly graphitic carbon (C) with mica, quartz, and possible feldspar

Fossil Sand Dollar (Echinoidea)

Phylum Echinodermata, Class Echinoidea (likely Dendraster or Scutella)

Ferruginous Sandstone with Quartz Inclusions

Clastic Sedimentary Rock (Iron-rich Sandstone)

Felsic gneiss, likely granitic gneiss

Quartz–feldspar–mica gneiss; commonly quartz + plagioclase/K-feldspar + biotite or hornblende

Mixed Rock and Mineral Collection

Mixed Assemblage (includes Quartz, Jasper, Feldspar, and Turquoise-colored stones)

Gneiss (specifically a Granitic Gneiss)

Gneiss (typically composed of Quartz, Feldspar, and Mica/Amphiboles)

Green Jasper (with Quartz veining)

Jasper (Silica-rich microcrystalline variety of Quartz), formula: SiO2

Sandstone (likely Arkosic or Quartzose)

Sandstone (SiO2 with inclusions)

River Stone (likely Siltstone or fine-grained Sandstone)

Clastic Sedimentary Rock (Lithic Wacke / Siltstone)

Sandstone, Quartzite, and River Pebbles

Silicon Dioxide (SiO2) based Sedimentary/Metamorphic structures

Siltstone with Quartz Vein

Siltstone (composed of Quartz and Clay minerals) with a hydrothermal Quartz vein (SiO2)

Gneiss (specifically Pink Gneiss)

Gneiss (high-grade regional metamorphic rock)

Small brown-gray mineral fragment

Indeterminate; possibly weathered quartz-, feldspar-, or iron-oxide-bearing rock

Petrified Wood

Silicified Wood (SiO2)

River Stone (likely Quartzite or Chert)

Sedimentary rock composed of Silicon Dioxide (SiO2)

Gneiss with Quartz Vein

Gneiss (containing SiO2 vein)

Chert Pebble

Microcrystalline Quartz (SiO2)

Banded iron formation fragment (likely hematite–magnetite ironstone)

Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and microcrystalline quartz (SiO₂)

Zebra Jasper (with Chlorite/Epidote)

Silicon Dioxide (SiO2) with inclusions