Sedimentary (Secondary Mineral) Within Igneous

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Thunderegg (specifically a Jasper/Agate-filled Geode nodule)

Silicon Dioxide (SiO2) within Rhyolitic Matrix

Banded Flint (Polished Stripe Flint)

Silicon Dioxide (SiO2) - variety of Chert

Red Granite

Phaneritic Felsic Igneous Rock

Garnet (Almandine variety)

Almandine, Fe3Al2(SiO4)3

Sandstone Concretion

Septarian or Carbonate-cemented Sandstone Concretion

Ironstone Concretion

Limonitic/Hematitic Concretion

Sandstone Geode (Ironstone Concretion)

Arenite with Limonite/Hematite matrix (SiO2 with Fe-oxides)

Chalcedony in Matrix

Silicon Dioxide (SiO2)

Agate (Beads)

Silicon Dioxide (SiO2)

Amethyst (as a jewelry accent)

Amethyst (Silicon Dioxide SiO2 with Iron impurities)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Chalcedony (Common Opal/Chert variety)

Silicon Dioxide (SiO2)

Ironstone Concretion (Moqui Marble)

Hematite/Goethite Concretion (Fe2O3 / FeO(OH))

Snowflake Obsidian

Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Ruby in Zoisite

Anyolite (Ruby in Zoisite)

Clear Quartz Crystal

Quartz (Silicon Dioxide, SiO2)

Granitic Pegmatite with Schorl Tourmaline

Granitic Pegmatite (Schorl: NaFe3Al6(BO3)3Si6O18(OH)4)

Jasper (Iron-stained)

Silicon Dioxide (SiO2) with iron oxide inclusions

Yellow Jasper

Cryptocrystalline Quartz (SiO2)

Scoria (Vesicular Basalt)

Scoria (Extrusive Igneous Rock)

Carnelian (Orange Agate)

Silicon Dioxide (SiO2)

Carnelian

Carnelian (Cryptocrystalline Quartz, SiO2)

Agate

Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony

Amethyst

Amethyst (SiO2 with iron impurities)

Sandstone (Quartzose Sandstone)

Clastic sedimentary rock (primarily SiO2)

Milky Quartz with Iron Oxide Staining

Quartz (Silicon Dioxide, SiO2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert (often called Flint when dark or found in chalk)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Granite

Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz Vein / Milky Quartz

Silicon Dioxide (SiO2)

Limonite (vibrant yellowish-brown iron oxide)

Limonite (FeO(OH)·nH2O)

Blue Apatite

Apatite-(CaF), Ca5(PO4)3F

Dalmatian Stone (Dalmation Jasper)

Aplite with Arfvedsonite inclusions

Chert (Jasper/Common Opal mix)

Microcrystalline Quartz (SiO2)

Jasper (Yellow Jasper)

Silicon Dioxide (SiO2) with iron inclusions

Ironstone Concretion (Limonite/Hematite Nodules)

Ironstone (principally Limonite FeO(OH)·nH2O or Hematite Fe2O3 mixed with silica/clay)