Minerals

Weathered basaltic river pebble

Basalt, likely altered or partially vesicular basalt

Clear quartz crystal

Quartz (SiO₂), likely a small rough or naturally fractured crystal

Milky quartz

Quartz (silicon dioxide, SiO₂)

Pegmatitic granite, strongly weathered

Granite/pegmatite composed mainly of quartz, feldspar, and mica

Dark veined metamorphic rock, likely serpentinite

Serpentinite; predominantly serpentine-group minerals, possibly with magnesite or calcite veins

Iron-Stained Quartz Pebble

Quartz (Silicon Dioxide, SiO2) with Iron Oxide Inclusion/Staining

Weathered quartz-rich metamorphic rock, likely milky quartz or quartzite

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

Milky quartz

Quartz, silicon dioxide (SiO₂)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Gneiss

Gneiss (High-grade Metamorphic Rock)

Gneiss

Gneiss

Banded Gneiss

Gneiss (Metamorphic Rock)

Diorite

Diorite

Green schist (probable)

Chlorite–mica schist; exact mineralogy cannot be confirmed from the photograph

Quartz with Sericite and Cinnabar

Silicon Dioxide (SiO2) with muscovite/sericite and mercury sulfide (HgS)

Greenschist (Chlorite Schist)

Greenschist (containing Chlorite, Actinolite, and Epidote)

Granite Gneiss

Gneiss (high-grade metamorphic rock)

Green-and-white mottled stone, possibly serpentinite

Likely serpentinized ultramafic rock; exact identification is uncertain from the photograph

Granite cobble

Granite, a coarse-grained felsic intrusive igneous rock, chiefly quartz, potassium feldspar, plagioclase, and dark biotite or hornblende

Mixed rock specimens; the gray-green piece is likely chlorite-bearing schist, with granite and light-colored quartz-rich rocks also visible

Tentative: chlorite schist (a foliated metamorphic rock); other visible pieces may include granite and quartzite

Diorite (River Rock/Cobble)

Intermediate Plutonic Igneous Rock (Diorite)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Banded Gneiss

Gneiss

Diorite

Diorite (Intermediate intrusive igneous rock)

Diorite

Phaneritic intermediate plutonic rock

Banded Metamorphic Rock

Gneiss or Schist

Chrysocolla in Cuprite

(Cu,Al)2H2Si2O5(OH)4 · nH2O (Chrysocolla) and Cu2O (Cuprite)

Vesicular basalt (scoriaceous basalt)

Basalt, primarily plagioclase, pyroxene, and iron-rich olivine; vesicular variety may be termed scoria

Banded gneiss pebble

Gneiss, composed chiefly of quartz, feldspar, and mica/amphibole

Mica Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

Limonite / Goethite (Iron Ore Mineral nodule)

FeO(OH)·nH2O / FeO(OH)

Quartz-bearing pegmatitic rock with feldspar

Granitic pegmatite; chiefly quartz (SiO₂), feldspar, and mica

Likely weathered quartz-bearing rock fragment

Indeterminate; appears to contain quartz (SiO₂) with iron-oxide staining, possibly from quartzite, granite, or pegmatite

Polished serpentine (likely green serpentinite)

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

Limonite

FeO(OH)·nH2O

Limonite

FeO(OH)•nH2O

Limonite

FeO(OH)•nH2O

Limonite

FeO(OH)•nH2O

Limonite

FeO(OH)·nH2O

Limonite

FeO(OH)•nH2O

Limonite

FeO(OH)•nH2O

Limonite

FeO(OH)·nH2O