Rock

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Serpentine-rich metamorphic rock

Serpentinite, likely antigorite/lizardite with accessory magnetite or chromite

Shale

Lutaceous sedimentary rock

Unidentified Rock

Unknown

Generic Rock Fragment

Rock Fragment

Mica Schist

Mica Schist (primarily Muscovite or Biotite sheet silicates)

Bivalve Seashell Fossil

Class Bivalvia

Granite

Felsic intrusive igneous rock

Quartz with Host Rock

Silicon Dioxide (SiO2)

Blue-gray quartz-rich rock, possibly blue aventurine or sodalite-bearing stone

Probable quartz–feldspar aggregate; exact identification requires testing

Dark gray fine-grained rock fragment

Likely basalt (possibly andesite); exact identification is limited by the photograph

Quartz-rich gravel fragment

Quartz (silicon dioxide, SiO₂), possibly with feldspar or carbonate inclusions

Yellow Chert or Jasper

Microcrystalline Quartz (SiO2)

River Pebble (Quartz/Jasper)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Fossiliferous Chert with Brachiopod Impression

Chert (SiO2) containing Brachiopoda fossil remains

Alluvial stream gravel (mixed rock specimens)

Polymictic fluvial deposit; likely mixtures of quartzite, sandstone, shale, chert, basalt, and granite-derived minerals

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, possibly altered granite

Weathered mafic rock, likely basalt

Basalt; primarily plagioclase feldspar, pyroxene, and minor olivine or iron oxides

Conglomeratic gravel / lithified alluvial deposit

Polymictic conglomerate or pebble-rich sandstone (likely weakly cemented)

Biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite granitoid; exact identification requires testing

Red granite or granitic gneiss cobble

Quartz–feldspar–mica rock; likely granite, possibly gneiss

Pink-and-black granite

Biotite-bearing granite, chiefly quartz, feldspar, and biotite mica

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous or dolomitic

Orbicular granite (likely rapakivi-type granite)

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Slickenside

Tectonic Fault Scarp Surface

Quartz Veined Basalt

Mafic Volcanic Rock with Microcrystalline Quartz (SiO2)

Coarse-grained granite or granitic pegmatite fragment

Granite; primarily quartz, feldspar, and mica

Weathered limestone or dolostone

Calcite-rich limestone (CaCO₃), possibly dolomite-bearing

Pink Granite

Phaneritic Quartz-Feldspar Plutonic Rock

Shale

Shale (clastic sedimentary rock composed of silt and clay-sized particles)

Dalmatian Jasper / Dalmatian Stone

Peralkaline Rock (Silicon Dioxide with Amphibole inclusions)

Shale

Fissile mudstone (Shale)

Quartz Geode

Silicon dioxide (SiO2)

Basalt

Extrusive Igneous Rock

Ulexite

NaCaB5O6(OH)6·5H2O

Basalt

Aphanitic Mafic Igneous Rock

Vesicular Basalt (Lava Rock)

Basalt (Vesicular Variety)

Serpentine

Antigorite, Lizardite, or Chrysotile (Mg, Fe)3Si2O5(OH)4

Quartzite

Quartzite (primarily SiO2)

Sandstone (Ferruginous)

Arenite with Iron Oxide (Limonite/Hematite) coating

Quartz Vein in Basalt

Silicon Dioxide (SiO2) in Mafic Igneous Rock