Unknown (Likely Sedimentary Or Metamorphic)

Petrified Wood (Silicified Wood)

Silicified Paleoflora (mainly Quartz, SiO2)

Clear quartz fragment

Quartz (silicon dioxide, SiO₂)

Banded gneiss

Felsic biotite–quartz–feldspar gneiss

Polished gray pebble, likely quartzite or chert

Quartzite (mostly SiO₂), tentative identification

Likely tumbled hematite or magnetite

Hematite (Fe₂O₃) or magnetite (Fe₃O₄)

Banded gneiss (likely orthogneiss or paragneiss)

Gneiss; composition commonly quartz + feldspar + mica, with possible amphibole/biotite

Tumbled garnet-bearing metamorphic rock

Likely garnet schist or garnet-bearing gneiss; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃

Milky quartz vein fragment

Quartz (silicon dioxide, SiO₂), massive or granular variety

Weathered quartz-rich pebble (tentative)

Likely quartz/chalcedony, SiO₂, possibly iron-stained

Mixed tumbled river pebbles and beach stones

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

Riverstone (likely Gray Slate or Siltstone)

Metamorphosed fine-grained sedimentary rock (Argillite/Slate)

Tumbled quartz (likely milky quartz)

Quartz — silicon dioxide, SiO₂

Likely weathered gneiss or granite fragment

Quartz–feldspar–mica aggregate; probably granitoid gneiss, identification uncertain from the photograph

Weathered quartz-rich pebble

Quartzite or silicified sandstone; predominantly microcrystalline quartz (SiO₂)

Petrified Wood

Silicified Wood (primarily SiO2)

Quartz-rich sandstone or quartzite fragment

Quartz sandstone; possibly weakly metamorphosed quartzite (SiO₂-dominant)

Honey-colored quartz cluster

Quartz, silicon dioxide (SiO₂), likely iron-stained or included quartz

Weathered schist or foliated metamorphic rock

Mica schist, possibly phyllite; exact identification requires a fresh surface and testing

Pyrite

Iron Sulfide (FeS2)

Blue-gray metamorphic rock, likely slate or phyllite

Fine-grained foliated metapelite; commonly mica- and chlorite-rich

Granitic Gneiss

Gneiss (High-grade Metamorphic Rock)

Coarse-grained gray metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss (probable)

Weathered quartz-bearing rock, possibly iron-stained quartzite

Quartzite (mostly SiO₂), tentatively identified

Pyrite-bearing rock (likely pyrite schist or pyritized shale)

Pyrite (FeS₂) in a fine-grained schistose or shale matrix

Quartz vein in weathered host rock

Quartz (SiO₂), likely in a weathered metamorphic or igneous matrix

Garnet-bearing metamorphic rock

Likely garnet schist or garnet-bearing mica schist; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃

Garnet-Bearing Gneiss

Garnetiferous Feldspathic Gneiss

Gneiss (Metamorphic Cobble)

Gneiss (High-grade Regional Metamorphic Rock)

Rounded quartz-rich pebble

Quartz-bearing lithic clast; exact rock type indeterminate from image

Mica-bearing metamorphic rock, likely schist

Muscovite/biotite mica schist with quartz and feldspar

Banded metamorphic river cobble, likely gneiss or metasedimentary rock

Quartz–feldspar–mica gneiss or quartzite with cross-cutting quartz veins

Magnetite / Iron Ore (likely Hematite-Magnetite mix)

Magnetite (Fe3O4)

Polished jasper pebble

Microcrystalline quartz (SiO₂), commonly with iron-oxide inclusions

Banded limestone or marble fragment

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

Dark gneiss or banded metamorphic rock

Banded quartz–feldspar–mica gneiss; exact identification requires testing

Coarse-grained metamorphic rock, likely gneiss or schist

Probable biotite-quartz-feldspar gneiss/schist; exact identification requires a fresh surface and tests

Dark gray metamorphic cobble, likely slate or phyllite

Foliated metapelite; possibly slate/phyllite composed mainly of quartz, mica, and chlorite

Banded metamorphic rock, likely gneiss

Foliated gneiss; chiefly quartz, feldspar, and dark mica/amphibole

Graphite-rich metamorphic rock (likely graphite schist)

Graphite schist; predominantly graphitic carbon (C) with mica and quartz

Likely weathered quartz-rich rock fragment

Uncertain; possibly quartz-bearing granitic or metamorphic material (SiO₂-dominant)

Iron-rich quartzite or weathered ironstone

Quartzite, predominantly SiO₂, with limonite/goethite (FeO(OH)·nH₂O) staining

Quartz-bearing weathered rock

Massive to drusy quartz (SiO₂), possibly in a feldspathic or carbonate host