Sedimentary Rock (Specifically A Chemical Sedimentary Rock, Or A Chert If Considered Purely Mineral Aggregate)

Chert (Jasper/Flint variety)

Microcrystalline quartz (SiO2)

Chert (Greenish-Grey variety)

Microcrystalline quartz (SiO2)

Limestone

Calcareous sedimentary rock (primarily Calcium Carbonate, CaCO3)

Sandstone (with man-made markings)

Arenite (composed primarily of Quartz, SiO2)

Sandstone with Liesegang Rings

Arenite with secondary Iron oxide (Limonite/Goethite) precipitation

Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Chert (Jasper-rich)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Quartz Conglomerate

Quartz Conglomerate (clastic sedimentary rock)

Red Jasper (specifically Brecciated Jasper)

Silicon Dioxide (SiO2) with Hematite inclusions

Chalcedony (specifically Agate or Common Opal variety)

Cryptocrystalline Silica (SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Quartz Geode

Silicon Dioxide (SiO2)

Sandstone (likely Arkosic or Lithic)

Clastic Sedimentary Rock (SiO2 with accessory minerals)

Chert (variously Flint or Jasper gravel)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Conglomerate

Conglomerate (Clastic sedimentary rock)

Sandstone (Ferruginous)

Arenite (with Iron Oxide cement)

Conglomerate

Conglomerate (clastic sedimentary rock)

Sandstone (likely Arkosic or Lithic Sandstone)

Clastic Sedimentary Rock (SiO2 with assorted minerals)

Chert (often called Flint in this context)

Silicon Dioxide (SiO2)

Druzy Quartz Geode (likely Smokey Quartz variety)

Silicon Dioxide (SiO2) - specifically a geode formation lined with druzy quartz crystals, with a likely brownish hue indicating smokey quartz.

Chert (often called Flint when dark)

Microcrystalline silicon dioxide (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Chert (variously identified as Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Gneiss (with Quartz-Feldspar vein)

Gneiss (high-grade metamorphic rock) containing Quartz (SiO2) and Feldspar (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8)

Gneiss (with iron staining)

Gneiss

Hematite Nodules (Moqui Marbles style)

Iron Oxide (Fe2O3)

Pink Granite

Phaneritic Felsic Igneous Rock (Granite)

Conglomerate

Clastic sedimentary rock (Conglomerate)

Sandstone (Ferruginous)

Arenite (with Iron Oxides)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Gneiss (Granitic Gneiss)

Gneiss (from German Gneis, related to 'spark')

Druzy Quartz on Matrix (likely Limestone or Sandstone)

Silicon Dioxide (SiO2) with various trace impurities

Chert with Desert Varnish

Cryptocrystalline Quartz (SiO2) with Manganese/Iron oxide coating

Sandstone (Weathered Cobble)

Clastic Sedimentary Rock (primarily SiO2)

Banded Gneiss

Gneiss (Metamorphic rock of variable mineralogy, often quartz-feldspar base)

Clay (as a rock-forming material)

Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)

Hag Stone

Perforated Chert (Microcrystalline Silica, SiO2)

Limestone

Calcium Carbonate (CaCO3)

Quartz Pebble (Chalcedony/Agate variety)

Silicon Dioxide (SiO2)

Druzy Quartz Geode (Oco or Moroccan variety)

Silicon Dioxide (SiO2)