Mineral (Chalcedony)

Green Jasper

Microcrystalline Quartz (Chalcedony), SiO2

Brecciated Jasper

Silicon Dioxide (SiO2) with iron impurities

Tumbled jasper

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

Tumbled yellow jasper

Jasper, microcrystalline quartz (SiO₂) with iron-oxide inclusions

Sardonyx or Carnelian Agate

Silicon Dioxide (SiO2) with iron impurities

Ocean Jasper

Orbicular Quartz (SiO2)

Tumbled chalcedony (likely carnelian or yellow jasper)

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

Dyed Purple Agate Sliced

Silicon Dioxide (SiO2) with artificial pigment

Polished jasper (likely brecciated or red jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide pigments and possible breccia fragments

Red jasper (likely iron-rich chert)

Microcrystalline quartz, SiO₂, colored mainly by hematite/goethite

Red jasper (probable)

Microcrystalline quartz/chalcedony (SiO₂) colored by iron oxides

Polished jasper and banded agate specimens

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

Tumbled jasper or iron-rich chert

Microcrystalline quartz (SiO₂), likely colored by iron oxides

Polished brecciated jasper (likely septarian or iron-rich jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and possibly calcite or other rock fragments

Jasper

Silicon dioxide (SiO2)

Blue Lace Agate

Microcrystalline Quartz (Chalcedony), SiO2

Agate

Silicon Dioxide (Chalcedony), SiO2

Chalcedony (Quartz Pebbles)

Silicon Dioxide (SiO2)

Moss Agate

Silicon Dioxide (Chalcedony variety)

Tree Agate

Chalcedony (SiO2) with Dendritic inclusions

Tree Agate

Silica (SiO2) with Chlorite inclusions

Milky quartz (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Yellow Agate

Silicon Dioxide (SiO2)

Polished banded agate

Microcrystalline quartz (chalcedony), SiO₂

Tumbled pale quartz/chalcedony fragment

Quartz (SiO₂), possibly microcrystalline chalcedony

Blue Quartz (Dumortierite Quartz)

Silicon Dioxide with Aluminum Borosilicate (SiO2 + AlAl6BSi3O18)

Dendritic Quartz

Silicon Dioxide (SiO2) with Manganese Oxide inclusions

Moss Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe/Chlorite)

Polished agate/geode fragment

Microcrystalline quartz (chalcedony), SiO₂, with possible calcite or quartz cavity lining

Jasper

Silicon dioxide, SiO2

Grape Agate

Chalcedony (Silicon Dioxide, SiO2)

Chrysoprase

Silicon dioxide with nickel impurities (SiO2 + Ni)

Agate

Silicon Dioxide (SiO2)

Botryoidal chalcedony (likely white quartz/chalcedony)

Microcrystalline quartz, SiO₂; possibly partly altered carbonate or opaline silica

Polished jasper pebble

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored by iron oxides

Yellow Jasper

SiO2

Carnelian

Silicon dioxide (SiO2) with Iron Oxide impurities

Banded Agate (Carnelian-Agate)

Silicon Dioxide (SiO2)

Polished Agate Geode

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Polished agate (likely moss or plume agate)

Microcrystalline quartz (SiO₂), chalcedony variety; exact variety is uncertain from the photo

Jasper Agate

Cryptocrystalline quartz, SiO2

Bloodstone

Heliotrope (Cryptocrystalline Quartz, SiO2)