Sedimentary (Volcanic)

Carnelian

Carnelian (SiO2)

Chalcedony (Agate/Carnelian type)

Silicon Dioxide (SiO2)

Jasper

Silicon dioxide (SiO2) with impurities

Yellow sulfur and polished pink jasper/chalcedony specimen

Native sulfur (S); pink jasper, microcrystalline quartz (SiO₂), possibly with iron-oxide or manganese staining

Reddish weathered volcanic rock, probably andesite

Andesite (fine-grained plagioclase–pyroxene volcanic rock), possibly altered basalt

Weathered volcanic rock, likely basaltic andesite

Basaltic andesite (fine-grained plagioclase–pyroxene rock; provisional visual identification)

Agate

Silicon dioxide (Chalcedony), SiO2

Common Opal / Chert

Hydrated silica (SiO2·nH2O) or Microcrystalline Quartz (SiO2)

Quartz Geode Fragment

Crystalline Silicon Dioxide (SiO2)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide impurities

River Stone (Basalt or Siltstone)

Mafic Volcanic Rock or Clastic Sedimentary Rock

Quartz Geode

Silicon Dioxide (SiO2)

Red Jasper

Jasper (Silicon Dioxide, SiO2 with Fe2O3 inclusions)

Banded Chalcedony (Agate)

Silicon Dioxide (SiO2)

Agate

Silicon dioxide (Chalcedony), SiO2

Tumbled Agate

Silicon Dioxide (Chalcedony variety), SiO2

Polished carnelian

Carnelian, orange-red chalcedony (microcrystalline quartz, SiO₂)

Polished jasper cabochon

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

Tumbled brecciated jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), with iron-oxide-rich breccia fragments

Red jasper

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

Tumbled red jasper

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

Tumbled carnelian

Carnelian, a translucent chalcedony variety of quartz (SiO₂), colored mainly by iron oxides

Carnelian (orange chalcedony)

Chalcedony, microcrystalline quartz (SiO₂), iron-colored variety

Polished yellow-orange chalcedony (likely carnelian)

Chalcedony, microcrystalline quartz (SiO₂), iron-colored variety commonly called carnelian

Chalcedony in Matrix

Silicon Dioxide (SiO2)

Carnelian

Carnelian (Cryptocrystalline Quartz, SiO2)

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Blue Opal in Matrix

Hydrated Silica (SiO2·nH2O)

Tumbled red jasper or mahogany obsidian

Microcrystalline quartz (SiO₂), likely jasper; alternative: volcanic glass (obsidian)

Agatized or Silicified Fossil/Coral, or Jasper

SiO2

Jasper

Silicon Dioxide (SiO2), Microcrystalline Quartz

Chalcedony

Silicon Dioxide (SiO2)

Red jasper (likely polished/tumbled)

Jasper, microcrystalline quartz/chalcedony (SiO₂) colored by iron oxides

Tumbled red/orange jasper

Jasper, microcrystalline quartz (chalcedony; SiO₂) with iron-oxide impurities

Tumbled brown-blue stone, possibly sodalite-bearing jasper

Likely quartz-rich jasper with blue sodalite or dumortierite; identification is uncertain from the image

Tumbled jasper

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

Red jasper (probable polished chalcedony/jasper)

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

Polished jasper

Microcrystalline quartz (SiO₂), commonly iron-oxide-rich

Tumbled jasper

Microcrystalline quartz (SiO₂), commonly iron-rich jasper

Likely tumbled amber or orange chalcedony

Uncertain from image; possibly amber (fossilized resin, chiefly C10H16O) or carnelian (microcrystalline quartz, SiO₂)

Red jasper fragment

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

Jasper

Silicon Dioxide (SiO2)