Amorphous Solid

Schist

Mica Schist (Medium-grade metamorphic rock)

Petrified Wood

Silicified Wood (SiO2)

Gold Nugget

Native Gold (Au)

Limonitic Scoria (Vesicular Basalt with Iron Staining)

Highly vesicular basalt heavily stained by Limonite [FeO(OH)·nH2O]

Mixed stream gravel and cobbles

Polylithic alluvial deposit; individual clasts are not identifiable at this resolution

Vesicular Basalt / Scoria (with Iron Oxide Alteration)

Vesicular Basalt

Druzy Quartz Geode (Partially Open)

Silicon Dioxide (SiO2) within Sedimentary Host Rock

Red Quartzite / Ferruginous Quartzite

Quartzite (primarily SiO2 with Fe2O3 inclusions)

Black Onyx

Silicon Dioxide (SiO2)

Pink Quartzite

Quartzite (primarily SiO2)

Yellow Chalcedony (Carnelian/Yellow Agate)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Ruby in Fuchsite

Corundum (Al2O3) in Chrome-Mica (K(Al,Cr)2(AlSi3O10)(OH)2)

Quartz Geode

Silicon Dioxide (SiO2)

Petrified Wood

Fossilized wood / Silicified wood

Turquoise jewelry beads/earrings

Turquoise, hydrated copper–aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O; possibly reconstructed or imitation turquoise

Banded Agate (Onyx Variety)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Glauconite (Green Sandstone)

Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2

Quartzite

Quartzite (SiO2)

Petrified Wood

Silicified Wood (Permineralized wood)

Petrified Wood

Silicified wood (primarily SiO2 - Silicon Dioxide/Quartz)

Petrified Wood

Silicified Wood (SiO2 as Quartz/Chert/Chalcedony)

Petrified Wood

Silicified Wood (SiO2)

Malachite specimen

Malachite, Cu₂CO₃(OH)₂, commonly intergrown with chrysocolla and minor copper oxides

Agate Geode

Cryptocrystalline Quartz (SiO2)

Quartz Geode

Crystalline Silver Oxide (SiO2) in Calcareous Host

Fossil-bearing limestone collection

Bioclastic limestone, commonly containing fossilized corals, bivalves, gastropods, and other marine invertebrates; composition primarily calcite (CaCO₃)

Pink tourmaline-bearing pegmatite (likely lepidolite-rich)

Lithium-rich granitic pegmatite; probable elbaite tourmaline (Na(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄) with lepidolite mica

Petrified Wood

Silicified Wood (SiO2)

Pink Quartz (Inclusion-rich Quartzite)

SiO2 (Silicon Dioxide) with Iron Oxide / Hematite inclusions

Microcrystalline Limestone Pebble

Carbonate sedimentary rock (Calcium Carbonate, CaCO3)

Petrified Wood

Fossilized plant material (Silicon dioxide - SiO2)

Petrified Wood (Silicified Fossil)

Silicified Wood (SiO2)

Black Onyx

Silicon Dioxide (SiO2) with cryptocrystalline structure

Sandstone (Pebble)

Sandstone (SiO2 dominated with minor feldspar/clay)

Agate Geode

Chalcedony (SiO2 - Silicon Dioxide)

Petrified Wood

Silicified Wood (primarily SiO2)

Wonderstone (Liesegang Sandstone)

Silicified Sandstone with Liesegang Rings (SiO2 + FeO(OH))

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Formation

Sandstone (Quartzose)

Arenite (SiO2 based typically)

Petrified Wood

Fossilized wood, permineralized wood (typically composed of SiO2)

Petrified Wood

Silicified wood (primarily Silicon Dioxide, SiO2)

Carnelian ring

Carnelian, a red-orange variety of chalcedony (microcrystalline quartz, SiO₂)