Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material)

Quartz Geode (likely within Limestone or Dolomite matrix)

Quartz (SiO₂)

Tufa

Calcareous Tufa (Calcium Carbonate, CaCO3)

Not a geological specimen

N/A (man-made object)

Basalt with Quartz/Feldspar Vein

Amygdaloidal Basalt with Plutonic intrusion (SiO2/KAlSi3O8)

Sandstone

Arenite

Biotite Schist

Biotite Schist (Rich in K(Mg,Fe)3AlSi3O10(OH)2)

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sunstone

Plagioclase feldspar (with Copper or Hematite inclusions)

Labradorite

Labradorite (Plagioclase Feldspar Series: (Ca,Na)(Al,Si)4O8)

Amazonite

Potassium Feldspar (Microcline), K(AlSi3O8)

Chert (Flint)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Sandstone (Clastic sedimentary rock, predominantly SiO2 with Fe2O3 cement)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Sandstone

Arenite (SiO2 based)

Chert (varieties include Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chrysocolla on Matrix

Hydrated copper phyllosilicate (Cu,Al)2H2Si2O5(OH)4·nH2O

Moonstone (bead form)

Potassium Aluminum Silicate (KAlSi3O8) - a variety of Orthoclase Feldspar

Granite

Granite (Felsic intrusive igneous rock)

Petrified Wood

Silicified Wood (SiO2)

Sandstone

Arenite (composed primarily of SiO2)

Moss Agate

Silicon Dioxide with inclusions (SiO2 + Fe/Mn/Mg)

Sandstone (likely with Borings or Vesicular Basalt)

Clastic Sedimentary Rock (Sandstone)

Sandstone

Arenite (composed primarily of SiO2)

Sandstone

Arenite (primarily SiO2)

Pink Granite

Phaneritic Felsic Igneous Rock (Granite)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Conglomerate

Conglomerate rock

Red Sandstone (Iron-Rich)

Arenite (Fe2O3)

Sandstone (specifically Banded Sandstone)

Clastic sedimentary rock (primarily SiO2)

Granitic Pegmatite

Granite Pegmatite (coarse-grained intrusive igneous rock)

Sandstone (likely Quartzose Sandstone)

Arenite (composed primarily of SiO2)

Sandstone (with potential iron-oxide weathering)

Arenite (SiO2 based)

Yellow Chert (Jasper)

Silicon Dioxide (SiO2)

Amygdaloidal Basalt

Amygdaloidal Basalt containing Zeolite or Quartz (SiO2/Silicates)

Sandstone with Liesegang Rings

Arenite with Iron Oxide Concretions

Sandstone (with Limonite staining)

Arenite (primarily SiO2 with FeO(OH)·nH2O)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone (specifically Lithic or Quartz Arenite)

Arenite (composed primarily of SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with iron oxide cement)

Pyrite on Limestone

Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix

Sandstone (Ferruginous)

Sandstone (primarily SiO2 with Iron Oxide cement)

Sandstone (Quartzose Sandstone)

Arenite (primarily SiO2)