Sedimentary (Secondary Classification: Cryptocrystalline Quartz)

Jasper pebble

Silicon dioxide (SiO2) with iron oxide inclusions

Sandstone

Arenite (Secondary classification based on grain size)

Sandstone Cobble

Arenite (Secondary classification based on grain size)

Quartz-rich chalcedony (likely silicified rock)

Microcrystalline quartz, SiO₂; possibly silicified limestone or jasper

Quartz-rich rock fragment, possibly chert or weathered quartz

Microcrystalline quartz (SiO₂), tentative identification

Granite (likely biotite granite)

Coarse-grained granitic rock; chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende

Polished kambaba jasper

Orbicular stromatolitic jasper; microcrystalline quartz (SiO₂) with chlorite/amphibole-rich inclusions

Chalcedony

Cryptocrystalline Quartz (SiO2)

Conglomeratic breccia

Clast-supported polymictic conglomerate/breccia, cemented by silica- or carbonate-rich matrix

Polished leopard jasper (orbicular or brecciated jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide and other mineral inclusions

Druzy Chalcedony (Agate Geode)

Silica (SiO2) - Cryptocrystalline Quartz with druzy macrocrystalline quartz

Dalmatian Stone

Dalmatian Jasper (a misnomer) / Perthitic Feldspar Rock

Red jasper pebble

Microcrystalline quartz (chalcedony), SiO₂, colored by iron oxides

Chalcedony (Agate/Carnelian pebbles)

Cryptocrystalline Quartz (SiO2)

Agate Pebble / Quartz Pebble

Cryptocrystalline Quartz (SiO2)

Chert with Quartz Veining

Microcrystalline Silica (SiO2)

Chert (with Quartz Veining)

Microcrystalline Quartz (SiO2)

Chalcedony (Agate) Pebble

Silicon Dioxide (SiO2)

Chert (River Pebble)

Cryptocrystalline Quartz (SiO2)

Zebra Jasper

Tektite variety of Silicon Dioxide (SiO2) with inclusions

Granite or granitic rock fragment

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

Banded Agate

Cryptocrystalline Quartz (SiO2)

Quartz-rich rock, likely milky quartz vein material

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

Breciated Chert

Brecciated Chert (Microcrystalline Quartz, SiO2)

Agate

Cryptocrystalline Quartz (SiO2)

Chalcedony in Limestone Host Rock

Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)

Chert (Jasper/Agate variety)

Cryptocrystalline Quartz (SiO2)

Jasper

Cryptocrystalline Quartz (SiO2)

Granite countertop slab

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

Yellow Quartz (Chert/Chalcedony)

Silicon Dioxide (SiO2) with iron inclusions

Red Jasper (possibly with Quartz or Hematite)

Silicon Dioxide (SiO2) with iron oxide impurities

Chert pebble

Cryptocrystalline Quartz (SiO2)

Red Siltstone

Siltstone (composed mainly of SiO2 and Fe2O3)

Agate

Cryptocrystalline Silicon Dioxide (SiO2)

Banded Agate

Cryptocrystalline Quartz (SiO2)

Polished red gemstone pendant, likely red jasper or brecciated jasper

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

Jasper (specifically Bloodstone/Heliotrope or Dark Green Jasper)

Cryptocrystalline Quartz (SiO2) with inclusions

Flint Nodule

Chert (Cryptocrystalline Quartz, SiO2)

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Rough Agate/Chert Nodules

Cryptocrystalline Quartz (SiO2)

Banded Chert

Cryptocrystalline Quartz (SiO2)

Agate (Carnelian Agate with Quartz Matrix)

Silicon Dioxide (SiO2)