Sedimentary (Volcanic)

Vesicular basalt (scoria-like volcanic rock)

Vesicular basalt, primarily plagioclase feldspar, pyroxene, and olivine

Trace Fossil (Lichenandites or Rhynie Chert Chert with Microfossils)

Trace fossil in microcrystalline quartz (SiO2)

Polished purple-gray stone, possibly lepidolite or purple jasper

Lepidolite (K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂) or quartz-rich jasper

Quartz (Druzy)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified wood (SiO2)

Opal

Hydrated silicon dioxide (SiO2·nH2O)

Tumbled Agate (Dyed Blue)

Silicon Dioxide (Chalcedony variety)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

River Stones (Basalt and Sedimentary Rock)

Basalt (dark specimen) and Siltstone/Mudstone (reddish specimen)

Weathered iron-rich river pebbles

Likely ferruginous chert or iron-stained siliceous/conglomeratic rock; exact identification is uncertain from the photograph

Orbicular jasper (orbicular chert/jasper)

Silica-rich microcrystalline quartz (chalcedony), SiO₂, with iron-oxide and other mineral inclusions

Green Moss Agate

Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite

Jasper (likely brecciated or iron-stained jasper)

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

Jasper

Silicon Dioxide (SiO2) with iron and magnesium inclusions

Jasper

Jasper (Silicon Dioxide, SiO2)

Geode (Unopened)

Silicon Dioxide (SiO2) in sedimentary vugs

Red jasper pebble

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

Orbicular jasper (orbicular chert), likely ocean jasper

Silicified microcrystalline quartz (chalcedony), SiO₂, with iron-oxide and/or clay-rich orbicules

Quartz Geode

Silicon Dioxide (SiO2) in a sedimentary or volcanic host

Quartz Druzy (Geode Fragment)

Silicon Dioxide (SiO2)

Jasper

Microcrystalline quartz (SiO2) with impurities

Chalcedony / milky quartz flake

Microcrystalline quartz (SiO₂), likely chalcedony; possibly a worked quartzite or chert fragment

Quartz Geode

Silicon Dioxide (SiO2)

Tumbled red-brown jasper

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

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Jasper

Silicon dioxide (SiO2)

Red Jasper

Silicon Dioxide with Hematite impurities (SiO2 + Fe2O3)

Rounded dark-gray cobble, likely basalt

Basalt (fine-grained mafic volcanic rock; identification is provisional from the image)

Chalcedony Rose

Silicon Dioxide (SiO2)

Jasper

Silicon dioxide (Microcrystalline Quartz, SiO2)

Chalcedony (Agate Pebble)

Silicon Dioxide (SiO2)

Kambaba Jasper

Rhyolite (Volcanic rock) or Stromatolite (debated)

Picture Jasper

Silicified sedimentary or volcanic rock (primarily SiO2)

Chalcedony

Silicon Dioxide (SiO2)

Chalcedony with Druzy Quartz

Silicon Dioxide (SiO2)

Tumbled Carnelian and Quartz Mix

Silicon Dioxide (SiO2) with iron oxide impurities

Jasper

Silicon dioxide (SiO2) with impurities

Chalcedony (Agate/Carnelian)

Cryptocrystalline Quartz (SiO2)

Chalcedony on Matrix

Silicon Dioxide (SiO2)

Mixed Mineral Collection

Multi-mineral Assemblage (Quartz, Jasper, Obsidian, Pyrite, etc.)

Weathered jasper-rich breccia

Silicified iron-rich breccia; primarily microcrystalline quartz (SiO₂) with iron oxides/hydroxides