Sedimentary Rock (Technically A Microcrystalline Quartz Mineral Aggregate)

Tumbled jasper pebble

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

Quartz (Chert/Chalcedony variety)

Silicon Dioxide (SiO2)

Bauxite

Hydrated aluminum oxides (mixture of gibbsite, boehmite, and diaspore)

Bauxite

AlOx(OH)3-2x (mixture of Gibbsite, Boehmite, and Diaspore)

Banded Chert

Microcrystalline Quartz (SiO2)

Chert Pebble

Microcrystalline Quartz (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Green Aventurine

Aventurine (variety of Quartz - SiO2)

Chert / Flint

Silicon Dioxide (SiO2)

Chert Pebble with Quartz Veins

Microcrystalline Quartz (SiO2)

Chert Pebble with Quartz Veining

Microcrystalline Quartz (SiO2)

Common Pebble / Sedimentary Rock Fragment

Lithified clastic sediment

Chert (Common Opal or Flint variant)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Greywacke with Quartz Vein

Greywacke (immature sandstone) with SiO2 inclusions

Quartzite Pebble (Microcrystalline Quartz / Chert)

Silicon Dioxide (SiO2)

Quartz-rich rock fragment, possibly chert or weathered quartz

Microcrystalline quartz (SiO₂), tentative identification

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Sandstone (Common Quartz Pebble/Rock)

Sedimentary rock / Quartz arenite

Druzy Quartz on Chert/Siltstone

Silicon Dioxide (SiO2) on Microcrystalline Silica/Siltstone matrix

Chalcedony Geode

Silicon Dioxide (SiO2)

Tumbled brown-and-cream stone, likely jasper or chert

Microcrystalline quartz (SiO₂), probably jasper/chert; exact identification requires testing

River Cobble (Quartzite or Sandstone)

Clastic sedimentary rock (primarily SiO2)

Kambaba Jasper

Stromatolite Jasper (Microcrystalline Quartz with Fossilized Cyanobacteria)

Jasper

Silicon Dioxide (SiO2)

Dalmatian Jasper

Peralkaline rhyolite with Arfvedsonite inclusions

Quartz-veined Sandstone

Sedimentary rock with quartz vein (SiO2)

Lapis Lazuli (Tumbled Specimen)

Lapis Lazuli (Aggregate rock containing Lazurite: (Na,Ca)8(AlSiO4)6(SO4,S,Cl)2)

Milky Quartz in Conglomerate Matrix

Silicon Dioxide (SiO2) within Clastic Sedimentary Rock

Flint or chert fragment

Microcrystalline quartz (SiO₂), likely flint/chert

Polished brown jasper pebble

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

Orbicular Rhyolite (Rainforest Jasper)

Orbicular Rhyolite

Kambaba Jasper

Stromatolite (Fossilized Algae)

Quartz-rich chalcedony (likely silicified rock)

Microcrystalline quartz, SiO₂; possibly silicified limestone or jasper

Weathered chert or siliceous limestone

Microcrystalline quartz (SiO₂), possibly with carbonate minerals

Geode

Quartz nodule / Chalcedony-lined cavity

Chalcedony on Matrix (Botryoidal Agate)

Silicon Dioxide (SiO2)

Chert (Commonly known as Flint)

Microcrystalline Quartz (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Veined Limestone (Micrite) with Quartz/Calcite Veins

Calcium Carbonate (CaCO3) with Silicate or Carbonate inclusions

Chert (Flint Pebbles)

Microcrystalline Quartz (SiO2)

Ocean Jasper

Silicon Dioxide (SiO2) with various inclusions