Mineral (Chalcedony)

Chalcedony on Ironstone

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3/FeOOH)

Geode

Quartz / Chalcedony nodule

Geode

Quartz / Chalcedony nodule

Polished orange agate (likely carnelian)

Chalcedony, microcrystalline quartz (SiO₂); orange-red variety commonly called carnelian

Moss Agate

Silicon dioxide (SiO2) with inclusions

Tumbled chalcedony (likely brown agate)

Chalcedony, microcrystalline quartz (SiO₂); possibly agate

Polished yellow chalcedony (likely lemon agate or yellow jasper)

Microcrystalline quartz, SiO₂

Tumbled chalcedony (likely milky agate)

Microcrystalline quartz, SiO₂; chalcedony/agate variety

Tree Agate

Chalcedony (SiO2)

Tumbled chalcedony (likely pale agate or quartz)

Chalcedony, microcrystalline SiO₂

Spherulitic Agate / Moss Agate

Chalcedony (SiO2) with mineral inclusions

Dendritic Agate or Moss Agate Nodules (Septarian-like)

Chalcedony with mineral inclusions (SiO2)

White Chalcedony (Agate)

Silicon Dioxide (SiO2)

Orange carnelian (possibly dyed agate) pendant

Cryptocrystalline quartz (chalcedony), SiO₂

Polished agate/jasper nodule

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide impurities

Polished white agate or chalcedony bead

Microcrystalline quartz (SiO₂), likely chalcedony/agate with iron-oxide staining or a brown mineral inclusion

Tumbled blue chalcedony/agate (likely glassy silica material)

Microcrystalline quartz, SiO₂; possibly blue chalcedony or dyed agate

Polished jasper pebble

Jasper, an opaque microcrystalline variety of quartz (SiO₂), often chalcedony with iron-oxide inclusions

Tumbled brown jasper (likely)

Microcrystalline quartz, SiO₂; jasper is an opaque variety of chalcedony

Polished red jasper

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

Red jasper (likely tumbled)

Microcrystalline quartz, chiefly SiO₂, colored red by iron oxides

Agate

Agate (Chalcedony), SiO2

Polished orange agate beads

Chalcedony, microcrystalline quartz (SiO₂), commonly sold as agate

Yellow jasper carving

Jasper, an opaque microcrystalline variety of quartz (SiO₂), shaped as a butterfly

Flower Agate

Chalcedony (SiO2) with inclusions

Purple Chalcedony (likely dyed Agate)

Silicon Dioxide (SiO2)

Polished agate (likely chalcedony)

Microcrystalline quartz, SiO₂; agate is banded chalcedony

Polished brecciated jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), with angular fragments cemented by silica or iron oxides

Jasper / Chert (river tumbled)

Microcrystalline Quartz (SiO2)

Ocean Jasper

Spherulitic Chalcedony (SiO2)

Black Onyx

Silicon Dioxide (SiO2)

Raw pink chalcedony (likely pink agate/jasper)

Microcrystalline quartz, SiO₂ (chalcedony); impurities may include iron oxides and other silicates

Tumbled blue chalcedony (likely blue lace agate)

Microcrystalline quartz, SiO₂; chalcedony with possible agate banding

Small tumbled stone, possibly moss agate

Likely chalcedony (microcrystalline SiO₂); exact identification is uncertain from the image

Chert or chalcedony nodule

Microcrystalline quartz (SiO₂), possibly weathered chert

Jasper

Microcrystalline Quartz (SiO2)

Carnelian Agate

Silicon Dioxide (SiO2)

Likely rough carnelian (orange-brown chalcedony)

Chalcedony, microcrystalline quartz (SiO₂); variety possibly carnelian

Druzy agate/geode fragment

Quartz (SiO₂) crystals lining a chalcedony-rich cavity, likely an agate geode

White Jade / White Chalcedony

Nephrite Jade (Ca2(Mg,Fe)5Si8O22(OH)2) or Chalcedony (SiO2)

Agate

Cryptocrystalline quartz (SiO2)

Jasper

Chalcedony (SiO2)