Synthetic Material (Not A Rock Or Mineral)

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood

Silicified Wood (SiO2)

Rounded gray metamorphic cobble, likely quartzite or gneiss

Quartz-rich metamorphic rock; possibly quartzite (mostly SiO₂) or banded gneiss

Dark vesicular volcanic rock, likely basaltic scoria

Scoria (vesicular basalt; composition commonly plagioclase, pyroxene, and iron-rich glass)

Schist

Schist (Foliated Metamorphic Rock)

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Granite (Polished Countertop Surface)

Plutonic Igneous Rock (Felsic)

Red Tuff / Sandstone

Rhyolitic Tuff / Pyroclastic Volcanic Rock

Sandstone (Red)

Arenite (primarily SiO2 with Fe2O3)

Vesicular Basalt (Scoria)

Vesicular Basalt

Dalmatian jasper (likely orbicular microgranite)

Quartz–feldspar–biotite/pyroxene microgranite; commonly marketed as Dalmatian jasper

Sandstone (with Iron Oxide)

Quartz Arenite / Ferruginous Sandstone (SiO2 with Fe2O3)

Red Sandstone

Arenite (SiO2 with Fe2O3)

Gneissic Schist

Gneiss-schist (Metamorphic rock)

Sandstone

Sedimentary Rock (Quartz Arenite)

Weathered sandstone or limestone fragment

Likely quartz-rich sandstone or micritic limestone; exact identification requires testing

River Pebble (Gravel)

Clastic sedimentary rock (likely Siltstone or Mudstone pebble; SiO2 with various impurities)

Flagstone (Sandstone)

Clastic Sedimentary Rock (composed of quartz and feldspar)

Polished green stone, likely serpentine or altered basalt

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

Polished porphyritic basalt (likely)

Basalt, a fine-grained mafic volcanic rock; visible inclusions may be olivine, feldspar, or vesicle infillings

Quartz (Quartz Pebble)

Silicon Dioxide (SiO2)

Quartz with inclusions

Silicon Dioxide (SiO2)

Epidosite

Epidosite (Metasomatic calcium-aluminum silicate rock)

Sandstone (Quartzite-rich)

Clastic sedimentary rock (SiO2 primary)

Amethyst-bearing quartz cluster

Quartz, SiO₂; purple coloration from irradiation and trace iron

Serpentine

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

Weathered quartz-rich rock, possibly milky quartz or quartz-bearing granite

Quartz (SiO₂), potentially with feldspar and iron-oxide staining

Quartz Pebble

Silicon Dioxide (SiO2)

Granitic Pebble (Glacial Erratic)

Granite

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2)

Sandstone (Sedimentary Rock)

Arenite (SiO2 based)

Chert (Flint Nodules)

Chert (Silicon Dioxide, SiO2)

Polished yellow jasper or opaque chalcedony bead

Microcrystalline quartz (SiO₂), likely iron-oxide-stained jasper

Chevron Amethyst

Silicon Dioxide (SiO2) with iron impurities

Flowerstone

Porphyritic Basalt or Porphyritic Andesite

Red Sandstone

Arenite (with Iron Oxide cement)

Travertine (Tufa)

Chemical Limestone (CaCO3)

Likely weathered quartz-rich stone

Indeterminate; possibly quartz-bearing granite or milky quartz

Amygdaloidal Basalt with Agate/Quartz Infill

Basalt with Secondary Silicate Mineralization (SiO2)

Red Sandstone

Sandstone (principally Quartz, SiO2, with Iron Oxide hematite cement)

Granite Cobble

Granite

Red Sandstone

Sandstone (hematitic/iron-rich quartzite or arenite)