Sedimentary Rock (Metamorphosed)

Iron-rich quartzite or jasper fragment

Quartzite, predominantly SiO₂, with hematite/goethite iron oxides

Weathered granite or granitic gneiss

Granite; primarily quartz, potassium feldspar, plagioclase, and biotite/hornblende

Biotite-rich granite or gneiss fragment

Dark mica-bearing granitoid; likely quartz–feldspar–biotite rock

Quartz-rich limestone or calcitic marble

Calcite (CaCO₃), possibly with quartz (SiO₂)

Iron-rich quartzite or ironstone

Ferruginous quartzite, likely quartz (SiO₂) with hematite/goethite (Fe₂O₃/FeO(OH))

Weathered granite or granitic gneiss pebble

Granite, primarily quartz, feldspar, and mica; possibly weakly foliated gneiss

Quartzite (or Ferruginous Quartzite)

Metamorphosed Quartz Sandstone (SiO2 with Fe2O3 impurities)

Banded iron formation fragment (likely hematite–magnetite ironstone)

BIF; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and silica as microcrystalline quartz (SiO₂)

Quartz-rich rock, likely milky quartz or quartzite

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

Tumbled brown stone, likely basalt or iron-stained quartzite

Indeterminate from photograph; possible basalt (mafic silicate rock) or quartzite (SiO₂)

Likely greenstone (serpentinized ultramafic rock)

Serpentinite, dominated by serpentine-group minerals (chrysotile/lizardite/antigorite), possibly with chlorite or epidote

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂); if quartzite, recrystallized quartz sandstone

Likely quartz-rich brown rock, possibly iron-stained quartz or quartzite

Quartz (SiO₂), possibly in quartzite or iron-oxide-bearing vein material

Quartz-rich pebble fragment

Likely milky quartz with iron-oxide staining; exact identification is uncertain from the photo

Serpentinite with green serpentine inclusion

Serpentinite; serpentine-group minerals, chiefly antigorite, lizardite, or chrysotile, with possible magnetite

Metamorphic schist, possibly chlorite–biotite schist

Schist; composition likely quartz, feldspar, mica (biotite/muscovite), and chlorite

Fuchsite-bearing green mica schist

Mica schist, chiefly muscovite/fuchsite mica with quartz; approximate mica composition KAl₂(AlSi₃O₁₀)(OH)₂

Likely amphibolite

Amphibolite, composed chiefly of hornblende (amphibole) and plagioclase feldspar

River Rock

Sedimentary clast

Weathered quartz-rich metamorphic rock, probably quartzite

Quartzite; predominantly microcrystalline SiO₂, possibly with feldspar and iron-oxide staining

White quartz-rich rock, possibly marble or quartzite

Quartz (SiO₂)-rich metamorphic stone; exact identification is uncertain from the photograph

Iron-stained quartz-rich rock, possibly limonite-bearing quartzite

Quartz (SiO₂) with iron oxides/hydroxides, chiefly hematite and goethite

Rhodonite-bearing metamorphic rock

Manganese-rich metamorphic rock, chiefly rhodonite (MnSiO₃), with quartz and manganese oxides

Fossil-bearing metamorphic rock, possibly schist with a fossil imprint

Micaceous schist; apparent fossil material is unidentified

Dark slate or fine-grained metamorphic rock

Slate; chiefly fine-grained phyllosilicates, quartz, and feldspar

Garnet-bearing granite or granitic gneiss

Quartz–feldspar granite with almandine garnet (Fe₃Al₂Si₃O₁₂), possibly garnet-bearing gneiss

Rounded gray cobble, likely quartzite or fine-grained sandstone

Quartzite (SiO₂), provisional identification

Weathered quartz-rich rock, possibly quartzite or iron-stained quartz

Quartz (SiO₂), likely in a quartzite matrix with iron-oxide staining

Weathered quartz-rich rock, likely iron-stained quartzite

Quartzite; predominantly quartz (SiO₂) with iron-oxide coatings

Weathered iron-rich quartzite (probable)

Quartzite, predominantly quartz (SiO₂) with iron-oxide staining

Rounded river pebble, likely quartz-rich sandstone or quartzite

Indeterminate quartz-rich clast; predominantly SiO₂

Tumbled greenish stone, likely serpentinite or greenstone

Probable serpentine-rich ultramafic rock; exact identification requires testing

Rounded granitic gneiss or granite cobble

Quartz–feldspar–mica rock; likely granitoid, possibly weakly gneissic

Weathered granite or granitic gneiss

Quartz–feldspar–mica granitic rock; possibly gneiss if foliation is present

Polished gray pebble, likely quartzite or chert

Quartzite (mostly SiO₂), tentative identification

Biotite-rich mica schist

Mica schist, dominated by biotite mica (K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂) with quartz and feldspar

Red-brown quartzite or quartz-rich sandstone

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with iron-oxide impurities

Shale

Argillite / Shale

Tumbled lapis lazuli

Lazurite-bearing calcite rock; lazurite approximately Na₃Ca(Si₃Al₃)O₁₂S

Greenstone

Metabasalt / Greenschist

Likely slate (possibly phyllite)

Fine-grained, foliated metamorphic rock; mainly mica and chlorite, with quartz and feldspar

Rounded quartz-rich pebble, likely quartzite or quartz sandstone

Quartzite (mostly SiO₂), possibly ferruginous quartz sandstone