Mineral_variety_of_chalcedony

Yellow jasper (likely iron-stained chert)

Microcrystalline quartz (SiO₂), chiefly chalcedony/quartz with iron-oxide pigments

Red jasper (likely tumbled or naturally worn)

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

Polished brown jasper pebble

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

Polished red jasper

Jasper, microcrystalline quartz (SiO₂)

Green Jasper

Silicon Dioxide (SiO2) with iron silicate inclusions

Tumbled jasper

Microcrystalline quartz (SiO₂), colored by iron oxides and other impurities

Tumbled yellow jasper

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

Polished orbicular jasper (likely ocean jasper)

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

Tumbled jasper

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

Coffee Bean Jasper

Silicon Dioxide (SiO2) with impurities

Yellow Jasper

Silicon Dioxide (SiO2) with high iron inclusion

Rhyolitic jasper / brecciated jasper

Silica-rich volcanic rock, chiefly microcrystalline quartz (SiO₂), with iron-oxide and clay/mineral impurities

Red Jasper

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Polished reddish-brown gemstone, likely carnelian

Carnelian: chalcedony, microcrystalline quartz (SiO₂), colored mainly by iron oxides

Polished banded agate

Agate, a banded variety of microcrystalline quartz (SiO₂; chalcedony)

Polished agate (likely)

Banded chalcedony, a microcrystalline variety of quartz (SiO₂)

Polished orbicular jasper (likely leopard-skin or brecciated jasper)

Microcrystalline quartz (SiO₂), with iron-oxide and other mineral inclusions; exact variety cannot be confirmed from the photo

Quartz (Chert / Agate / Chalcedony)

Silicon Dioxide (SiO2)

Iron-rich chert or jasper

Microcrystalline quartz (SiO₂), commonly colored by hematite/goethite

Botryoidal chalcedony (likely common opal)

Silica, SiO₂; chalcedony is microcrystalline quartz, while opal is hydrated amorphous silica (SiO₂·nH₂O)

Banded Carnelian

Carnelian (Silicon Dioxide / SiO2)

Carnelian

Carnelian (Silicon Dioxide - SiO2)

Blue-gray chalcedony (banded agate fragment)

Chalcedony, microcrystalline quartz (SiO₂), likely agate variety

Tumbled purple agate (likely amethyst-bearing agate)

Banded chalcedony, a microcrystalline variety of quartz (SiO₂); exact identification is uncertain from the image

Tumbled Agate and Chalcedony

Cryptocrystalline Quartz (SiO2)

Yellow Agate (Banded Chalcedony)

Silicon Dioxide (SiO2)

Red jasper (likely brecciated or iron-stained jasper)

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

Agate (specifically Botswana or Banded Agate variety)

Chalcedony (Silicon Dioxide, SiO2)

Amethyst geode halves

Amethyst (紫色 quartz), silicon dioxide (SiO₂), colored by iron impurities and irradiation

Red jasper (likely tumbled jasper/chert)

Microcrystalline quartz, SiO₂, colored red by iron oxides; exact identification from the photo is uncertain.

Red jasper (likely brecciated jasper)

Microcrystalline quartz/chalcedony (SiO₂) colored by iron oxides, with white quartz or calcite veining

Polished agate (likely Botswana or plume agate)

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

Banded agate (likely jasper/chalcedony nodule)

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

Polished bloodstone (heliotrope)

Chalcedony, microcrystalline quartz (SiO₂), colored by iron-oxide inclusions

Tumbled banded jasper (probable)

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

Polished red jasper beads

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

Polished moss agate

Moss agate, a microcrystalline quartz variety (SiO₂) with green chlorite/actinolite or iron-manganese inclusions

Tumbled bloodstone (heliotrope), probable

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

Jasper

Silicon dioxide (SiO2) with impurities

Banded agate (likely carnelian/chalcedony)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide coloration

Tumbled orbicular jasper (probable)

Jasper, microcrystalline quartz (SiO₂), with iron- and clay-rich inclusions

Green Jasper

Silicon Dioxide (SiO2) with iron silicate inclusions