Sedimentary Rock (Metamorphosed)

Quartz-bearing rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if metamorphosed

Weathered granite or granitic gneiss

Coarse-grained quartz–feldspar–mica rock; likely granite, possibly gneiss

Granite or granitic gneiss fragment

Felsic granitoid, chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Weathered quartz-rich rock, possibly quartzite

Quartzite (mostly SiO₂), though a feldspathic sandstone or weathered granite fragment is also possible

Weathered quartz-rich rock, likely milky quartz/quartzite

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

Quartz-bearing metamorphic rock, likely quartzite with dark mica/amphibole

Quartzite or quartz-rich schist; chiefly SiO₂ quartz with biotite, hornblende/amphibole, and iron-oxide staining

Copper-bearing metamorphic rock, likely bornite- or chalcopyrite-rich schist

Quartz–mica schist with disseminated copper sulfides; possible bornite (Cu₅FeS₄) and chalcopyrite (CuFeS₂)

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (silicon dioxide, SiO₂); exact specimen identification is uncertain from the image

Likely serpentinized ultramafic rock (serpentinite)

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with possible olivine, pyroxene, magnetite, and talc

Likely gray slate or fine-grained argillite fragment

Slate, a low-grade metamorphic rock derived from shale; exact identification is uncertain from the image

Rounded brown river pebble, likely quartzite

Quartzite (predominantly recrystallized quartz, SiO₂); identification is tentative from the image

Greenstone / serpentinized rock

Serpentinite, commonly dominated by serpentine-group minerals (antigorite, lizardite, or chrysotile)

Iron-rich quartzite or ferruginous metamorphic rock

Ferruginous quartzite, dominated by quartz (SiO₂) with hematite/goethite and minor iron oxides

Likely blue-gray stone, possibly slate or basalt

Indeterminate; candidates include slate (fine-grained metamorphic rock) or basalt (mafic igneous rock)

Serpentinized ultramafic rock (serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chromite, talc, and carbonate

Serpentinized ultramafic rock (serpentinite)

Serpentinite, dominated by serpentine-group minerals (lizardite/chrysotile/antigorite), with possible magnetite, talc, and brucite

Coarse-grained granite or granitic gneiss

Quartz–feldspar–mica granite; possibly foliated granitic gneiss

Rounded quartz-rich pebble

Probable arkosic sandstone or weathered quartzite; exact identification is uncertain from the image

Rounded quartz-rich pebble

Likely quartzite or quartz-rich sandstone pebble; SiO₂-dominant

Quartz-rich granite or granitic gneiss cobble

Granite; primarily quartz, feldspar, and mica, possibly with gneissic deformation

Slate or shale fragment

Slate; predominantly clay minerals, mica, and quartz (low-grade metamorphosed shale)

Graphite-bearing schist (probable)

Graphite schist; primarily quartz, mica, and graphite (carbon)

Likely gray granite or granitic gneiss

Granite: quartz–feldspar–mica aggregate; possibly foliated granitic gneiss

Rounded quartz-rich cobble, likely quartzite

Quartzite (mostly microcrystalline SiO₂), possibly quartz-rich sandstone or vein quartz

Quartzite

Quartzite (primarily SiO2)

Likely milky quartz or quartz-rich rock

Quartz, silicon dioxide (SiO₂); exact identification is limited by the blurry image

Serpentine-rich metamorphic rock

Serpentinite, likely antigorite/lizardite with magnetite and possible chlorite or talc

Likely weathered granite or granitic gneiss fragment

Granite: quartz + feldspar + mica; possibly gneiss if foliation is confirmed

Mica-rich rock, likely muscovite mica schist

Muscovite-bearing schist; muscovite KAl₂(AlSi₃O₁₀)(F,OH)₂

Likely quartz-rich rock (possibly milky quartz or quartzite)

Quartz-rich aggregate, predominantly silicon dioxide (SiO₂); exact identification is uncertain from the image

Dark gray metamorphic rock, likely slate or phyllite

Slate/phyllite; chiefly fine-grained mica, chlorite, quartz, and clay-derived minerals

Tumbled rhodonite

Rhodonite (MnSiO₃), commonly with manganese oxides and quartz

Rounded quartz-rich pebble, likely quartzite or chert

Quartzite (mostly microcrystalline SiO₂); exact identification requires hardness and acid tests

Quartz-rich pebble, likely milky quartz

Quartz (SiO₂), possibly weathered quartzite or chalcedony

Weathered quartz-rich rock, possibly quartzite

Quartzite (predominantly SiO₂), tentative identification

Granite or granitic gneiss

Quartz–feldspar–mica granitoid; possibly foliated gneiss

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and biotite/hornblende

Weathered granitic gneiss (probable)

Gneiss, chiefly quartz–feldspar–biotite; compositionally granitic

Weathered iron-stained quartzite or quartz vein rock

Quartz-rich rock, predominantly SiO₂, with limonite/goethite iron oxides

Serpentinite (likely serpentine-rich rock)

Serpentinite; chiefly serpentine-group minerals, Mg3Si2O5(OH)4

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if metamorphic

Iron-stained Quartzite

Metamorphosed Quartz (SiO2) with Hematite/Limonite impurities