Sedimentary Rock (Technically A Variety Of Chalcedony)

Tumbled agate/chalcedony (likely moss or plume agate)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide or mineral inclusions

Polished agate/chalcedony slab

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

Petrified Wood

Silicified wood (Quartz/Chalcedony replacement of organic matter)

Chert (Agatized)

Silicon Dioxide (SiO2)

Yellow Jasper

Silicon dioxide, SiO2

Agate

Silicon Dioxide (SiO2)

Polished red jasper

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

Red jasper

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

Tumbled red jasper

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

Carnelian

Chalcedony (SiO2)

Moss Agate

Silicon dioxide (SiO2) with inclusions

Agate

Chalcedony (Silicon Dioxide, SiO2)

Tumbled carnelian

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

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Chert (specifically Jasper)

Silicon dioxide (SiO2) with iron oxide inclusions

Satin Spar (Selenite)

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Tumbled jasper pebble

Jasper, microcrystalline quartz (SiO₂), commonly iron-oxide stained

Banded Calcite (often sold as Yellow Aragonite or Onyx)

Calcium Carbonate (CaCO3)

Dendritic Agate

Silicon Dioxide with Manganese or Iron Oxide inclusions (SiO2 + Mn/Fe)

Chert Nodule

Microcrystalline Quartz (SiO2)

Agate

Silicon dioxide (SiO2)

Agate

Silicon dioxide (SiO2)

Tumbled jasper or chert

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

Tumbled red jasper

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

Red jasper (likely rough jasper/chert)

Microcrystalline quartz (SiO₂), commonly colored by iron oxides

Chalcedony (Fire Agate or Carnelian variety)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chalcedony (Agate)

Silicon Dioxide (SiO2)

Tumbled banded agate (likely carnelian or sardonyx)

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

Tumbled chalcedony or agate

Microcrystalline quartz (SiO₂), likely pale agate/chalcedony

Polished/tumbled brown jasper

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

Polished Black Obsidian

Volcanic Glass (70-75% SiO2)

Jasper, possibly Brecciated Jasper or Ocean Jasper due to patterns and color

Silicon Dioxide (SiO2), a variety of Chalcedony

Jasper

Silicon Dioxide (SiO2)

Polished/tumbled agate or chert

Microcrystalline quartz (SiO₂), likely chalcedony with opaque impurities

Yellow Jasper

SiO2

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)

Black obsidian (likely polished)

Volcanic glass; chiefly rhyolitic silica-rich glass (approximately 70–80% SiO₂)

Yellow Jasper

Silicon Dioxide with Iron inclusions (SiO2)

Tumbled red jasper

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

Polished amber agate pendant/beads

Chalcedony (microcrystalline quartz), SiO₂, likely iron-stained yellow-orange agate

Tumbled carnelian

Carnelian, a red-orange cryptocrystalline chalcedony (SiO₂)

Tumbled jasper, likely red/brown jasper

Microcrystalline quartz (chalcedony), SiO₂, colored by iron oxides