Man Made Rock (Technosol)

Chert (Chalcedony/Flint)

Silicon Dioxide (SiO2)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Wishing Stone with Quartz Vein

Hydrothermal Quartz Vein in Metasedimentary Matrix (primarily SiO2)

Bivalve Fossil (Clam)

Class Bivalvia (Calcium Carbonate, CaCO3)

White Quartz Pebble

Silicon Dioxide (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Chert (varieties include Flint and Jasper)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Quartz Vein / Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Amethyst (Tumbled)

Purple Quartz (SiO2 with iron impurities and irradiation)

Petrified Wood

Silicified Wood (primarily SiO2)

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Quartz Vein in Schist

Quartz (SiO2) in Mica Schist

Ferruginous Quartz

Silicon Dioxide (SiO2) with Limonite/Hematite inclusions

Mookaite Jasper

Radiolarite (SiO2 with impurities)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Milky Quartz

Crystalline Silicon Dioxide (SiO2)

Black Tourmaline in Quartz

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4) in Silicon Dioxide (SiO2)

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Garnet Schist

Almandine Garnet-Mica Schist (X₃Y₂(SiO₄)₃)

Scoria (Lava Rock)

Vesicular Basalt / Scoria

Sandstone Geode (Unbroken)

Siliciclastic sedimentary rock (primarily Quartz)

Eclogite

Eclogite (Omphacite + Almandine-Pyrope Garnet)

Shale with Iron Oxide Staining

Fissile Mudstone (primarily clay minerals and quartz)

Sandstone

Arenite (primarily SiO2 with various cementing agents)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Sandstone (Greywacke/Lithic Sandstone)

Arenite (composed primarily of SiO2)

Stromatolite

Biogenic Sedimentary Rock (Lithified microbial mat)

Bauxite

Bauxite (Al2O3·nH2O)

Sandstone (Banded)

Clastic Sedimentary Rock (primarily SiO2)

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

Smoky Quartz

Silicon Dioxide (SiO2)

Basalt with Quartz Veins

Amygdaloidal Basalt (matrix) with Crystalline SiO2 (veins)

Granite

Granite (Felsic Plutonic Rock)

Snowflake Obsidian (or similar porphyritic volcanic rock)

Obsidian with Spherulites (if glassy), or Porphyritic Rhyolite/Andesite (if crystalline groundmass)

Brown Sandstone

Arenite (primarily Quartz and Feldspar, with Iron Oxide cement)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Emerald In Matrix

Beryl (Be3Al2Si6O18) with trace Chromium/Vanadium

Garnet Schist or Garnet-bearing Quartzite

Metamorphic rock containing Almandine Garnet (Fe3Al2(SiO4)3) and Quartz (SiO2)

Chert (Quartz Variety)

Chert (mostly SiO2 / Silicon Dioxide)