Rock

Porrphyritic pink granite (weathered)

Granite, commonly composed of quartz, alkali feldspar, plagioclase, and biotite/hornblende

Lichen-covered granite or granitic gneiss

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

Rounded weathered pebble

Likely fine-grained sandstone, siltstone, or weathered volcanic rock; exact identification is uncertain from the image

Banded gneiss (likely biotite-bearing)

Gneiss; quartz–feldspar–mica assemblage, with possible iron-oxide staining

Rounded sandstone pebble

Quartz-rich sandstone, commonly arkose or lithic sandstone

Veined Grey Metamorphic Pebble

Quartzo-feldspathic vein in Metabasalt / Serpentinite / Slate

Honey calcite (likely rough cleavage fragment)

Calcite, calcium carbonate (CaCO₃)

Quartz-veined Metamorphic Rock

Quartz-veined Schist or Gneiss

Quartz-rich rock, likely granite or quartz-bearing metamorphic rock

Undetermined; possibly granitic rock composed mainly of quartz and feldspar, with mica or other dark minerals

Likely basalt (possibly fine-grained gabbro)

Basalt; predominantly plagioclase feldspar, pyroxene, and commonly olivine

Polished petrified wood (agate/chalcedony replacement)

Silicified wood, chiefly microcrystalline quartz (SiO₂), often with iron-oxide coloration

Dark gray fine-grained stone, likely basalt

Basalt; mainly plagioclase feldspar, pyroxene, and sometimes olivine

Serpentine

Antigorite/Chrysotile group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al,Fe)2O5(OH)4)

Basalt

Extrusive Igneous Rock

Basalt

Afanitic Mafic Basalt

Basalt

Mafic volcanic rock (primarily plagioclase, pyroxene, and olivine)

Basalt with Plagioclase Phenocrysts

Porphyritic Basalt

Basalt with Iron Oxidation (Lattice/Veined)

Mafic Volcanic Rock (principally Plagioclase and Pyroxene)

Basalt with Quartz/Calcite Veins

Aphanitic Mafic Igneous Rock (Hydrothermal Veined)

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Conglomerate

Conglomerate (Detrital Sedimentary Rock)

Vesicular Basalt (Scoria)

Vesicular Basalt

Sandstone

Arenite (predominantly SiO2 quartz grains)

Red Sandstone

Arenite (SiO2 with Fe2O3)

Dalmatian jasper (often sold as Dalmatian stone)

Porphyritic alkali feldspar–quartz syenite, commonly with black arfvedsonite/aegirine-group amphibole inclusions

Quartz with Schist Inclusion

Crystalline Silicon Dioxide (SiO2) with Muscovite/Biotite Schist

Shale

Argillaceous sedimentary rock

Likely bituminous coal

Coal, predominantly carbon-rich organic matter; exact rank cannot be confirmed from the image

Druzy Quartz on Chalcedony Matrix

Silicon Dioxide (SiO2)

Shale (sub-type: Carbonaceous Shale)

Lutaceous Sedimentary Rock

Greywacke (River Pebble with Quartz Veins)

Greywacke (Indurated Sandstone); Veins: SiO2 (Quartz)

Quartzite River Rock

Quartzite (primarily SiO2)

Polished greenstone pebble

Likely serpentinite or chlorite-rich greenschist

Mixed Rock Collection

Polylithic Geological Specimen Mix

Rounded gray pebble, likely quartz-rich stone

Indeterminate; possibly quartzite or a weathered granitic pebble

Unakite

Epidote-Feldspar rock

Weathered quartz-bearing rock

Quartz-rich vein material; likely quartz with iron oxides and feldspar, exact rock type uncertain

Quartz Vein in Sandstone

Sandstone with Hydrothermal Quartz (SiO2)

Quartz-rich rock fragment

Likely quartz vein material, predominantly quartz (SiO₂); identification is tentative from the image

Porphyritic Basalt

Porphyritic Basalt

Likely quartz-rich rock fragment

Indeterminate; possibly quartz-bearing granite or quartzite

Sandstone (Iron-stained)

Arenite with Limonite/Hematite staining