Mineral (Cryptocrystalline Quartz)

Blue lace agate (likely dyed or color-enhanced)

Microcrystalline quartz (chalcedony), SiO₂

Quartzite and Jasper Pebbles

Quartzite (re-crystallized Quartz) and Cryptocrystalline Quartz (SiO2)

Tumbled orange chalcedony (likely carnelian)

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

Shiva Lingam

Cryptocrystalline Quartz and Iron Oxide

Tumbled jasper or chalcedony

Microcrystalline quartz (SiO₂), likely jasper/chalcedony

Carnelian

Carnelian (SiO2 with Fe2O3 impurities)

Botryoidal chalcedony (likely moss or plume agate)

Microcrystalline quartz, SiO₂; chalcedony with possible iron/manganese inclusions

Polished jasper pebble

Microcrystalline quartz, SiO₂, with iron-oxide and clay inclusions

Tumbled agate/chalcedony pebble

Microcrystalline quartz (SiO₂), likely brown/banded agate or jasper

Polished brown chalcedony (likely carnelian or sard)

Chalcedony, microcrystalline quartz (SiO₂); brown varieties are commonly termed sard, while reddish-orange material is carnelian

Moss Agate / Green Jasper

Silicon Dioxide (SiO2) with chlorite/hornblende inclusions

Pink Dyed Agate Geode Slice

Silicon Dioxide (SiO2) with artificial pigment

Polished blue chalcedony (likely seam agate)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide inclusions

Dyed Agate

Chalcedony (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Tumbled brown stone, likely jasper or iron-rich chert

Microcrystalline quartz (SiO₂), possibly iron-oxide-bearing jasper/chert

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Jasper Pebble

Microcrystalline Quartz (SiO2)

Chert (Flint variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Yellow or Tan Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chalcedony in Limestone Host Rock

Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)

Chert (often called Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (variations include Chalcedony and Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Polished brecciated jasper

Jasper (microcrystalline quartz, SiO₂), likely brecciated and iron-oxide stained

Jasper

Jasper (Cryptocrystalline variety of Quartz, SiO2)

Chalcedony (gray-white agate)

Microcrystalline quartz, SiO₂

Chert (often called Flint when dark or found in chalk)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

White quartz crystal (likely milky quartz)

Quartz, silicon dioxide (SiO₂); possibly chalcedony if the interior is cryptocrystalline

Botryoidal Chalcedony (Agate/Desert Rose Chalcedony)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chalcedony (River Stone)

Microcrystalline Quartz (SiO2)

Yellow jasper (likely polished/tumbled)

Microcrystalline quartz, SiO₂, colored by iron oxides; exact identification is uncertain from the image

Tumbled blue chalcedony (likely blue quartz/chalcedony)

Cryptocrystalline silica, SiO₂; likely chalcedony, possibly dyed or surface-coated

Banded Agate (specifically Carnelian Agate)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Quartz Vein in Basalt

Silica-infilled basaltic host rock

Botryoidal chalcedony/geode fragment

Microcrystalline quartz (SiO₂), likely limonite/goethite-stained chalcedony with druzy quartz

Chert (Chert Pebble)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (often called Flint in dark varieties)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (varieties include Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Polished/tumbled brown stone, likely brown jasper or chert

Microcrystalline quartz (SiO₂), probably jasper/chert; exact identification requires testing

Chalcedony with Druzy Quartz

Silicon Dioxide (SiO2)

Chalcedony Pebble

Silicon Dioxide (SiO2)