Sedimentary Rock (Technically A Variety Of Chalcedony)

Brown chalcedony (likely carnelian or agate fragment)

Microcrystalline quartz, SiO₂; iron-oxide-colored chalcedony

Red jasper

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

Agate (Carnelian Agate with Quartz Matrix)

Silicon Dioxide (SiO2)

Dyed Agate Geode

Silicon Dioxide (SiO2) - Chalcedony variety

Polished brown jasper pebble

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

Chalcedony in Matrix

Silicon Dioxide (SiO2)

Agate Nodule

Silicon Dioxide (Chalcedony), SiO2

Fancy Jasper

Silicon Dioxide (SiO2) with impurities

Jasper

Jasper (a variety of Chalcedony, SiO2)

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Tree Agate

Dendritic Agate (Silicon Dioxide, SiO2 with chlorite inclusions)

Dendritic Agate (Blue Chalcedony)

Silicon Dioxide (SiO2)

Jasper (Red/Yellow)

Silicon Dioxide (SiO2) with impurities

Tumbled jasper/chert pebble

Microcrystalline quartz (SiO₂), likely iron-stained jasper or chert

Tumbled orange chalcedony (likely carnelian)

Cryptocrystalline quartz, SiO₂; orange variety commonly called carnelian

Carnelian Beads

Silicon Dioxide (Variety of Chalcedony), $SiO_2$

Agate

Silicon Dioxide (SiO2) - variety: Chalcedony

Jasper with Quartz inclusions

Silicon Dioxide (SiO2)

Tumbled brown agate

Microcrystalline quartz (SiO₂), variety of chalcedony

Quartz Geode Fragment

Silicon dioxide (SiO2) within a nodule

Jasper

Silicon dioxide (SiO2)

Common Opal with Host Rock

Opal (Hydrated silica, SiO2·nH2O)

Carnelian (Orange Chalcedony)

Silicon Dioxide (SiO2)

Banded Agate (Tumbled)

Agate (Variety of Chalcedony/Quartz), SiO2

Carnelian

Silicon Dioxide, variety of chalcedony (SiO2)

Agate

Cryptocrystalline Silicon Dioxide (SiO2)

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Red Jasper

SiO2 (Silicon Dioxide) with Iron Oxide inclusions

Jasper / Chert (river tumbled)

Microcrystalline Quartz (SiO2)

Red Jasper (possibly Carnelian)

Silicon Dioxide with Iron Oxide inclusions (SiO2 + Fe2O3)

Red jasper

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

Polished brown jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), likely iron-rich brecciated or orbicular jasper

Chert

Silicon dioxide (Microcrystalline Quartz, $SiO_2$)

Tumbled jasper, likely brecciated or brown-green jasper

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

Dragon Blood Jasper

Epidote with Red Jasper inclusions (SiO2 and Ca2(Al,Fe)3(SiO4)3(OH))

Concrete fragment with Aggregate

Anthropogenic Concrete with Calcarious and Siliceous Aggregate

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Polished orange agate or chalcedony

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

Jasper

Silicon Dioxide (SiO2) with impurities

Yellow chalcedony or quartz fragment

Microcrystalline quartz, SiO₂ (tentative; possibly iron-stained chalcedony)

Onyx Marble (Banded Calcite)

Calcite (Calcium Carbonate, CaCO3)

Red Jasper

Jasper (Silicon Dioxide, SiO2 with Iron Oxide impurities)