Not A Rock Or Mineral (Anthropogenic Material)

Polished basalt pebble

Basalt, a fine-grained mafic volcanic rock; chiefly plagioclase, pyroxene, and iron-titanium oxides

Sandstone (Banded)

Clastic Sedimentary Rock (primarily SiO2)

Weathered iron-rich rock, possibly limonite/goethite-bearing breccia

Hydrated iron oxides/hydroxides, mainly limonite (mixture) and goethite, FeO(OH)·nH₂O

Weathered iron-rich rock, possibly laterite or limonite-bearing quartzite

Limonite/goethite mixture, commonly FeO(OH)·nH₂O, with possible quartz and iron oxides

Orbicular rhyolite (orbicular jasper-like volcanic rock)

Silica-rich rhyolite containing concentric feldspar–quartz orbicules, commonly with iron-oxide staining

Quartz vein material

Quartz (SiO₂), likely milky quartz with iron-oxide staining

Amethyst (rough purple quartz)

Quartz, SiO₂; purple color from trace iron and natural irradiation

Sandstone

Arenite (SiO2 primarily)

Sandstone

Sandstone (Siliciclastic Sedimentary Rock)

Sandstone (with potential iron-oxide weathering)

Arenite (SiO2 based)

Sandstone

Clastic sedimentary rock (Quartz arenite / Arkose)

Fossilized Shell

Invertebrate fossil (Bivalvia or Brachiopoda)

Small metallic-looking rock fragment

Uncertain; possibly galena-bearing ore or mica-rich schist

Likely iron-rich metamorphic rock (possibly hematite-rich ironstone)

Unidentified ferruginous rock; exact mineralogy cannot be determined from the image

Gneiss

Gneiss (High-grade metamorphic rock)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Tumbled yellow jasper or silicified rock fragment

Microcrystalline quartz (chalcedony), SiO₂, likely iron-oxide colored

Sandstone

Arenite (SiO2 based)

Sandstone

Arenite (SiO2 based)

Sandstone

Sandstone (SiO2 dominant)

Sandstone

Arenite (SiO2 based)

Orbicular jasper

Siliceous microcrystalline quartz (chalcedony), commonly sold as ocean jasper

Fossil bivalve shell

Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features

Tumbled granite pebble (probable)

Granite; quartz–feldspar–mica aggregate

Turquoise (likely stabilized or composite)

Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2)

Sandstone

Sedimentary Rock (Quartz arenite)

Pebble / Rounded Rock

Lithic fragment / Water-worn rock

Sandstone Pebble (River Rock)

Arenite (primarily SiO2)

Sandstone

Quartz Arenite / Clastic Sedimentary Rock

Chrysocolla-bearing rock (likely chrysocolla in quartz/limonite matrix)

Chrysocolla, hydrated copper aluminosilicate: (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O

Brachiopod Fossil

Phylum Brachiopoda

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Polished red jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides

Weathered quartz-rich rock fragment

Indeterminate; likely quartz-bearing silicate rock

Basalt with Quartz Veins

Basalt (with SiO2 veins)

Shale (or Mudstone)

Laminose Mudrock (composition: clay minerals, quartz, and mica flakes)

Likely weathered iron-rich quartz or chert

Microcrystalline quartz (SiO₂), possibly limonite/goethite stained

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite

Quartzite Geode or Crystalline Quartz Node

Silicon Dioxide (SiO2)

Possible weathered quartz-rich rock or iron-stained mineral fragment

Indeterminate; possibly quartz (SiO₂) with iron-oxide inclusions