Microcrystalline Quartz

Tumbled jasper pebble

Jasper, microcrystalline quartz (SiO₂), commonly iron-oxide stained

Green chalcedony (likely dyed or treated)

Chalcedony, microcrystalline quartz (SiO₂)

Weathered iron-rich chert or jasper

Microcrystalline quartz (SiO₂), commonly colored by iron oxides/hydroxides

Red jasper pebble

Jasper, microcrystalline quartz (SiO₂), colored mainly by iron oxides

Carnelian (a variety of Chalcedony)

SiO2 (Silicon Dioxide) with Iron Oxide impurities

Yellow Jasper

Jasper (Silicon Dioxide, SiO2)

Black Onyx

Silicon dioxide (SiO2) - Chalcedony variety

Iron-rich jasper or hematite-bearing chert

Microcrystalline quartz (SiO₂) with hematite/goethite (Fe₂O₃/FeO(OH))

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Weathered quartz-rich nodule, possibly agate or chalcedony

Microcrystalline quartz (SiO₂), potentially with iron-oxide staining or a druzy coating

Zebra Jasper

Silicon dioxide (microcrystalline quartz), SiO2

Weathered iron-rich chert or jasper

Microcrystalline quartz (SiO₂), variably stained by iron oxides

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), likely iron-stained jasper/chalcedony

Tumbled jasper (likely yellow/orbicular jasper)

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

Fossil Coral

Rugosa or Tabulata coral fossil (Calcium Carbonate, CaCO3)

Jasper-bearing Quartzite River Cobble

Tectonized Quartzite with Iron-Oxide (Hematite/Limonite) Veining

K2 Jasper (K2 Granite)

Azurite in Granite (Biotite Granite with Azurite inclusions)

Red Jasper

Silicon Dioxide with Iron Oxide impurities (SiO2 + Fe2O3)

Lake Superior Agate

Banded Chalcedony / Silicon Dioxide (SiO2)

Tumbled orange chalcedony

Chalcedony (microcrystalline quartz, SiO₂), likely orange carnelian

Chert (or Flint)

Microcrystalline Quartz (SiO2)

Banded chert pebble

Chert (microcrystalline quartz, SiO₂), likely ribbon-banded chert

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Translucent agate/chalcedony

Microcrystalline quartz (SiO₂), likely chalcedony with agate-like banding

Beach Pebbles and Jasper

Quartz / Microcrystalline Silicon Dioxide (SiO2)

Tumbled chalcedony (likely carnelian or yellow jasper)

Microcrystalline quartz, SiO₂; iron-oxide-bearing chalcedony/jasper

Tumbled brown chalcedony (likely carnelian/agate)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide coloration

Red jasper (likely iron-rich chert)

Microcrystalline quartz (SiO₂) colored by hematite/goethite

Blue chalcedony or common opal

Cryptocrystalline silica, SiO₂; likely pale blue chalcedony, possibly opal-A

Iron-rich brown chert or weathered ironstone

Chert (microcrystalline quartz, SiO₂), possibly limonitic/goethitic ironstone

Orbicular jasper (polished/tumbled)

Silica-rich microcrystalline quartz/chalcedony, commonly with iron-oxide or other mineral orbicules; composition varies by locality

Brown chalcedony (likely agate/jasper)

Chalcedony, cryptocrystalline SiO₂, with iron-oxide inclusions

Agate

Silicon Dioxide (SiO2) - Banded Chalcedony

Banded chert or flint pebble

Microcrystalline quartz (SiO₂), likely chert with a pale weathered/altered zone

Bloodstone (Heliotrope)

SiO2 (Silicon Dioxide with inclusions of Chlorite, Amphibole, or Hematite)

Brown chalcedony (likely carnelian/iron-stained quartz)

Microcrystalline quartz, SiO₂; brown coloration from iron oxides/hydroxides

Dalmatian Stone (commonly called Dalmatian Jasper)

Peralkaline Rock (mixed Feldspar, Quartz, and Arfvedsonite)

Botryoidal chalcedony (possibly quartz geode coating)

Microcrystalline quartz, SiO₂; botryoidal chalcedony

Tumbled chert or flint pebble

Microcrystalline quartz (SiO₂), likely chert

Yellow chert or jasper pebble

Microcrystalline quartz (SiO₂), likely iron-oxide-stained chert/jasper

Red Jasper

Silicon dioxide (SiO2) with iron oxide (Hematite) inclusions

Yellow Jasper

Silicon Dioxide (SiO2) with Goethite or Iron Oxide inclusions