Vesicular basalt (probable)
Basalt, mainly plagioclase feldspar and pyroxene, with possible olivine and iron oxides
igneous
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Fulonite (Fulgurite-like)
Fulgurite (SiO2 fused silica/lechatelierite)
Metamorphic (Pseudo-igneous)
Riverstone Quartzite (Water-worn Siltstone/Quartzite)
Metamorphosed Quartz-rich Arenite (SiO2)
metamorphic
Slate
Low-grade Metamorphic Rock (composed of quartz, illite, chlorite)
metamorphic
Nuummite
Nuummite (ortho-amphibole rock)
metamorphic
Granite Pebble (Salt and Pepper Granite)
Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Biotite/Amphibole)
igneous
Lichen-covered graywacke or granitic glacial cobble
Indeterminate; likely quartz–feldspar–mica rock, possibly weathered granite or granodiorite
igneous
Polished basalt with a quartz vein
Basalt, cut by milky quartz (SiO₂)
igneous
Granite Pebble (Porphyritic or Pink Granite)
Granite (felsic plutonic rock comprising Quartz, Potassium Feldspar, Plagioclase, and Biotite/Amphibole)
igneous
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Tumbled sodalite beads
Sodalite, Na8(Al6Si6O24)Cl2, commonly with minor white calcite or nepheline
mineral
Sandstone
Arenite
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Tumbled basalt (likely)
Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine
igneous
Chert (White Chert/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Chalcedony/Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Schist
Mica Schist
metamorphic
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Chert (Green River Chert)
Microcrystalline Quartz (SiO2)
sedimentary
Quartzite
Quartzite (composed primarily of SiO2)
metamorphic
Iron-stained quartz-rich rock, likely quartzite or silicified breccia
Quartz (SiO₂), possibly quartzite with limonite/goethite iron oxides
metamorphic
Chert / Flint
Microcrystalline quartz (SiO2)
sedimentary
Weathered pink granite fragment
Granite, chiefly quartz, potassium feldspar, and plagioclase feldspar with minor mica
igneous
Magnetite (Lodestone)
Iron(II,III) oxide (Fe3O4)
mineral
Likely basalt
Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase, clinopyroxene, and often olivine
igneous
Basalt
Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)
Igneous
Sandstone
Arenite
sedimentary
Serpentinite (probable)
Serpentinite; chiefly serpentine-group minerals, commonly lizardite, chrysotile, or antigorite, with possible magnetite and relict olivine/pyroxene
metamorphic
Reddish sandstone
Quartz-rich sandstone (arenite), commonly iron-oxide stained
sedimentary
Blue Obsidian
Volcanic Glass (SiO2 with inclusions)
igneous
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
igneous
Tumbled porphyritic granite
Granite, primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende
igneous
Polished turquoise
Turquoise — hydrated copper–aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O
gemstone
Foliated metamorphic rock, likely biotite schist
Mica schist, chiefly quartz, feldspar, and biotite mica
metamorphic
Basalt
Basalt
igneous
Porphyritic Rhyolite (Llanite or similar)
Porphyritic Rhyolite / Quartz-Feldspar Porphyry
igneous
Red Sandstone
Arenite (Ferruginous Sandstone)
sedimentary
Fossilized bivalve shell fragment
Fossil Mollusca, likely a bivalve (class Bivalvia); exact genus cannot be determined from the image
fossil
Gneissic Schist
Foliated Metamorphic Rock (Schist/Gneiss transition)
metamorphic
Polished ocean jasper (orbicular jasper)
Microcrystalline quartz (SiO₂), commonly with chalcedony and iron-rich alteration minerals
mineral
Pegmatitic granite
Granite, quartz–feldspar–mica assemblage
igneous
Yellow Quartz (Citrine Quartz Pebble)
Silicon Dioxide (SiO2)
mineral