Sedimentary (Secondary Classification: Cryptocrystalline Quartz)

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate quartz–feldspar aggregate; likely weathered granite (quartz, feldspar, minor iron oxides)

Chert (Vuggy Chert)

Silicon Dioxide (SiO2)

Chert with Calcite Veining

Microcrystalline Quartz (SiO2) with Calcium Carbonate (CaCO3) veins

Weathered quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂); likely quartzite if the granular texture is recrystallized sandstone

Agate (Geode nodule fragment)

Chalcedony (cryptocrystalline variety of Quartz), SiO2

Granite countertop slab

Granite; primarily quartz, feldspar, and mica (commonly biotite), with accessory amphibole/iron oxides

Chert (Banded Variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper influence)

Microcrystalline Quartz (SiO2)

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Quartz-rich rock, likely milky quartz vein material

Quartz (SiO₂), possibly quartzite or quartz-bearing pegmatite

Chert (containing Orbicular/Agate patterns)

Microcrystalline Quartz (SiO2)

Chert (Nodular)

Chert (Microcrystalline Quartz, SiO2)

Dyed Agate (Tumbled)

Silicon Dioxide (SiO2) - stained microcrystalline quartz

Rounded gray-brown cobble, likely weathered sandstone or quartzite

Tentatively quartz-rich sandstone (SiO₂-dominated); exact identification requires hardness and acid tests

Banded Agate (specifically Carnelian Agate)

Silicon Dioxide (SiO2)

Polished red gemstone pendant, likely red jasper or brecciated jasper

Jasper: microcrystalline quartz (SiO₂), commonly with hematite or iron-oxide inclusions

Granite or granitic rock fragment

Felsic intrusive igneous rock, typically quartz + feldspar + mica; exact species uncertain from the image

Bituminous Coal (with Anthracite or Vitrinite inclusion)

Organic-rich Sedimentary Rock (Carboniferous classification)

Quartz (Jasper / Chert)

Silicon Dioxide (SiO2)

Brecciated Jasper

Microcrystalline Quartz (SiO2)

Red Jasper with Quartz Vein

Microcrystalline Quartz (SiO2) with Hematite inclusions

Jasper or Chert with Quartz Vugs

Silicon Dioxide (SiO2)

Agate

Agate (Silicon Dioxide, SiO2)

Chert (with Quartz veins)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Chalcedony variety)

Silicon Dioxide (SiO2)

Chert (Jasper/Agate variant)

Microcrystalline Quartz (SiO2) with iron oxide inclusions

Chert with Quartz Veining

Silicon Dioxide (SiO2)

Red Jasper with Quartz Veins

Microcrystalline Quartz (SiO2) with Hematite impurities

Quartz-rich rock, possibly yellow chalcedony or weathered quartzite

Quartz (SiO₂), likely microcrystalline chalcedony with iron-oxide staining

Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Chert (containing Quartz veins)

Chert (SiO2)

Botryoidal Chalcedony (Agate)

Cryptocrystalline Quartz (SiO2)

Weathered sandstone or quartzite cobble

Quartz-rich sandstone; possibly weakly metamorphosed quartzite

Chalcedony (Yellow/Honey variety)

Microcrystalline Quartz (SiO2)

Quartz-rich breccia or silicified breccia

Cryptocrystalline quartz/chalcedony (SiO₂) with iron oxides and dark lithic fragments; exact classification is uncertain from the photograph

Jasper with Quartz Vein

Microcrystalline quartz (SiO2) and chalcedony with a quartz vein

Lunar Highlands Breccia (Meteorite)

Lunar Feldspathic Breccia

Jasper or Chert

Silicon Dioxide (SiO2)

Dyed Agate

Microcrystalline Quartz (SiO2) with artificial pigment

Bloodstone

Chalcedony (cryptocrystalline quartz)

Quartz-veined Chert

Silicon dioxide (SiO2)

River Pebble (likely Quartzite or Chert)

Sedimentary Clast (Silicon Dioxide dominant)