Sedimentary Rock (Metamorphosed)

Biotite Mica

Biotite, K(Mg,Fe)3AlSi3O10(F,OH)2

Iron-stained quartz-rich rock (likely ferruginous quartzite)

Quartz-rich rock stained by iron oxides, chiefly hematite (Fe₂O₃) and/or goethite (FeO(OH)); exact identification is uncertain from the photograph

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if the grains are fused

Likely iron-stained quartz or quartzite

Quartz (SiO₂), possibly quartzite; yellow-brown coloring likely from iron oxides

Slate or fine-grained shale

Slate; predominantly quartz, mica, and clay-derived minerals

Limestone

Calcium Carbonate (CaCO3)

Likely weathered granite or granitic gneiss

Granite–gneiss, chiefly quartz, feldspar, and mica

Weathered quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if recrystallized sandstone

Quartz-rich rock, likely quartzite or quartz vein fragment

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

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, with possible iron-oxide and dark mica/mineral inclusions

Rhodonite-bearing manganese ore

Rhodonite (MnSiO₃), with manganese oxides and quartz/calcite gangue

Iron-rich quartzite or weathered ironstone pebble

Quartzite, chiefly SiO₂, with iron-oxide minerals (hematite/goethite)

Likely slate or fine-grained metamorphic rock

Slate/phyllite; predominantly fine-grained mica, chlorite, and quartz

Quartz-rich stone tool or shaped mineral specimen

Likely milky quartz or quartzite (SiO₂); exact material cannot be confirmed from the image

Weathered gray stone, likely granite or gneiss

Probable granitic rock; exact identification is uncertain from the image

Iron-stained quartz-rich metamorphic rock (probable quartzite or hydrothermal vein rock)

Quartz-dominant rock; chiefly SiO₂, with iron oxides/hydroxides and minor sulfide minerals

Rounded quartz-rich pebble

Likely quartzite or quartz-rich sandstone; composition predominantly SiO₂

Polished greenstone (likely serpentinite or chlorite-rich schist)

Serpentinite/chlorite-rich ultramafic metamorphic rock; composition commonly dominated by serpentine-group minerals, chlorite, magnetite, and minor amphibole or pyroxene

Serpentinized ultramafic rock with magnesite

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with likely magnesite (MgCO₃) and minor chromite/magnetite

Blue-gray foliated metamorphic rock, likely slate or phyllite

Slate (fine-grained metamorphosed shale), possibly phyllite; mineral proportions cannot be confirmed from the image

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

Mostly quartz (SiO₂), with probable iron-oxide staining and minor feldspar or clay minerals

Weathered quartz-rich rock, possibly quartzite or quartz vein fragment

Quartzite (SiO₂-dominant), tentative identification

Quartz-bearing weathered rock, possibly quartzite or quartz vein fragment

Quartz (SiO₂), with iron-oxide staining and likely feldspathic impurities

Weathered granite or granitic gneiss

Granite–gneiss, composed mainly of quartz, feldspar, and mica

Unakite (or Epidote-rich Granite)

Unakite (Metamorphosed Granite consisting of Epidote, Orthoclase, and Quartz)

Likely basaltic rock or mafic metamorphic specimen

Basalt, possibly altered to amphibolite/greenstone; chiefly plagioclase and pyroxene, with possible chlorite, amphibole, and iron oxides

Likely serpentinized ultramafic rock (serpentinite)

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

Serpentinized ultramafic rock (likely serpentinite)

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

Pyrite-bearing metamorphic rock (probable pyrite schist)

Schist containing pyrite (FeS₂), with probable quartz and mica

Shale

Shale (clastic sedimentary rock)

Shale (or Mudstone/Siltstone)

Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)

Tumbled granite or granitic gneiss

Granite, typically quartz + feldspar + mica; possibly foliated granitic gneiss

Likely serpentinite (serpentine-rich rock)

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

Iron-rich quartzite or iron-stained quartz

Quartzite; predominantly quartz (SiO₂) with iron-oxide/hydroxide coatings, possibly minor mica or feldspar

Weathered iron-stained quartzite or sandstone cobble

Quartzite (quartz-rich rock), possibly ferruginous sandstone

Rounded quartz-rich cobble

Likely quartzite or quartz-rich sandstone; exact identification requires a hardness and acid test

Banded sandstone or quartzite fragment

Quartz-rich sandstone; possibly weakly metamorphosed quartzite

Rounded brown river pebble

Likely weathered quartz-rich sandstone or iron-stained quartzite; exact identification requires testing

Pyrite-bearing metamorphic rock (likely schist or quartzite)

Quartz–mica rock with disseminated pyrite; pyrite is FeS₂

Iridescent schist or phyllite

Micaceous quartz-rich schist/phyllite, likely containing muscovite or chlorite

Likely weathered mica-rich rock fragment

Probable schist, composed mainly of quartz, feldspar, and mica

Weathered granite or granitic gneiss

Granite–gneiss, chiefly quartz, feldspar, and biotite/amphibole