Sedimentary Rock (Altered)

Iron-stained quartz vein rock

Milky quartz (SiO₂) with limonite/goethite iron oxides, possibly in altered host rock

Quartz-veined breccia

Hydrothermal quartz–carbonate breccia; chiefly SiO₂ quartz with calcite/dolomite and altered host rock

Greenstone, possibly serpentine or altered basalt

Serpentinite (Mg₃Si₂O₅(OH)₄) or chlorite-epidote altered basalt; identification is uncertain from the image

Polished green stone, likely serpentine or altered basalt

Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄; exact identification requires testing

Copper ore-bearing rock (likely malachite/chrysocolla in a sulfide-rich matrix)

Cuprite–malachite/chrysocolla mineralization; probable copper sulfides such as chalcopyrite in altered host rock

Weathered iron-rich volcanic rock (probable basalt/andesite)

Altered basaltic to andesitic volcanic rock; composition likely plagioclase, pyroxene, and iron oxides

Fossilized Shell Impression / Siltstone Fossil

Bivalvia / Brachiopoda mold in Siltstone

Sandstone or Siltstone

Arenite (if sandstone)

Sandstone or Mudstone

Sedimentary Rock

Polished agate/geode slice

Chalcedony (microcrystalline quartz, SiO₂), likely agate with an altered druzy/quartz interior

Shale

Shale (Fine-grained clastic sedimentary rock)

Polished pink-and-green feldspar-bearing rock, likely unakite or aventurine granite

Unakite-like epidote–feldspar–quartz aggregate; composition commonly K-feldspar + quartz + epidote

Shale

Argillaceous sedimentary rock

Pumice (likely)

Pumice (extrusive igneous rock)

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Shale

Lutaceous sedimentary rock

Unakite

Granitic Unakite (Alteration rock composed of pink orthoclase feldspar, green epidote, and clear quartz)

Quartz–feldspar-bearing metamorphic rock, likely gneiss or migmatite

Band­ed quartzofeldspathic gneiss; chiefly quartz (SiO₂), feldspar, mica, and dark amphibole/biotite

Shale

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

Shale

Fissile mudstone (Shale)

Sandstone

Arenite

Phyllite (possibly low-grade greenish slate)

Foliated metamorphic rock composed mainly of very fine-grained quartz, mica, and chlorite; approximate composition varies and has no single fixed chemical formula

Shale fragment

Shale (clay mineral rich sedimentary rock)

Shale / Mudstone

Sedimentary rock (Claystone / Mudstone / Shale)

Brown Sandstone (River Rock)

Arenite

Biotite Mica

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

Shale

Clastic Sedimentary Rock

Sandstone

Clastic sedimentary rock (primarily SiO2)

Shale

Shale (claystone/mudstone)

Shale

Sedimentary Shale

Shale and Pebble Fragment

Sedimentary Rock (Mudstone/Shale with Silica Pebble)

Mudstone

Argillite / Siliciclastic sedimentary rock

Weathered basalt (possibly iron-stained volcanic rock)

Basalt; primarily plagioclase feldspar and pyroxene, commonly with olivine and iron oxides

Geode

Quartz nodule / Chalcedony-lined cavity

Shale

Laminated Fissile Pelite

Polished greenstone (likely serpentine or altered basalt)

Serpentinite, chiefly serpentine-group minerals; possible chlorite/actinolite-bearing greenstone

Sandstone pebble

Sandstone (mainly Quartz, SiO2)

Rhyolite (possibly porphyritic and altered)

Volcanic felsic rock; primarily quartz, alkali feldspar, plagioclase, and volcanic glass, with iron-oxide alteration

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Dyed blue howlite (turquoise imitation), possibly dyed magnesite

Howlite: Ca₂B₅SiO₉(OH)₅; the vivid blue color is artificial dye. Exact identification is uncertain from the photograph alone.

Fossil Shell

Invertebrate fossil (Mollusca)

Shale

Fissile mudrock (composed of clay-sized particles and detrital grains)