Sedimentary (Or Mineraloid)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Iron-stained Quartzite / Chert

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Agate (specifically a small Chalcedony nodule)

Agate (Cryptocrystalline variety of Quartz, SiO2)

Red Jasper

Jasper (SiO2) with Hematite (Fe2O3) inclusions

Satin Spar (Selenite Gypsum Sphere)

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Chert (Jasper type)

Microcrystalline Quartz (SiO2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Galena

Lead Sulfide (PbS)

Gneiss (specifically a water-worn pebble)

Gneiss

Garnet Schist

Almandine Garnet in Mica Schist (Fe3Al2(SiO4)3)

Yellow Calcite

Calcium Carbonate (CaCO3)

Galena

Lead(II) sulfide (PbS)

Orange Calcite

Calcium Carbonate (CaCO3)

Selenite (Satin Spar)

Gypsum (CaSO4·2H2O)

Quartz Geode (partially formed)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Carnelian

Carnelian Chalcedony (SiO2 with iron oxide impurities)

Banded Gneiss

Gneiss (complex metamorphic silicate rock)

Green Calcite

Calcite (CaCO3)

Quartz

Silicon Dioxide (SiO2)

Blue Chalcedony

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Aragonite Star Cluster

Aragonite (Calcium Carbonate, CaCO3)

Quartz Druzy on Geode Fragment

Silicon Dioxide (SiO2)

Potassium Feldspar

Orthoclase (KAlSi3O8)

Petrified Wood (Silicified Wood)

Silicified fossil wood (SiO2)

Gneiss

High-grade metamorphic rock (Gneiss)

White Quartz

Silicon Dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Orange Calcite

Calcium Carbonate (CaCO3)

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2

Quartz (specifically Clear Quartz or Rock Crystal)

Silicon Dioxide (SiO2)

Orange Quartz (or Tumbled Carnelian)

Silicon Dioxide (SiO2) with iron oxide inclusions

Quartz

Silicon Dioxide (SiO2)

Clear Quartz

Silicon Dioxide (SiO2)

Chert with Desert Varnish

Cryptocrystalline Quartz (SiO2) with Manganese/Iron oxide coating

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Jasper

Silicon Dioxide (SiO2) - Opaque Chalcedony

Chert (Yellow Jasper variant)

Silicon Dioxide (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Chert (Yellow/Brown variety)

Chert (SiO2)