Sedimentary Rock (Technically A Microcrystalline Quartz Mineral Aggregate)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Conglomerate with Quartzite Pebbles

Clastic sedimentary rock (Conglomerate)

Rough amber-colored quartz or calcite fragment

Likely quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing

Chert / Flint Nodule

Microcrystalline quartz (SiO2)

Chert (Basanite / Jasperoid)

Microcrystalline Quartz (SiO2)

Chert / Flint

Microcrystalline quartz (SiO2)

Iron-rich chert or jasper

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

Snowflake Obsidian

Hydrated Volcanic Glass with Cristobalite inclusions

Zebra Jasper

Silicon Dioxide (SiO2) with impurities

Chert (Flint)

Microcrystalline Quartz (SiO2)

Amethyst or Smoky Quartz Geode Slice

Crystalline Silicon Dioxide (SiO2) with iron impurities

Tumbled quartz-rich rock, possibly calcite or sandstone

Indeterminate from photograph; likely microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Bumblebee Jasper

Carbonate-rich volcanic sediment with arsenic and sulfur inclusions

Snowflake Obsidian

Volcanic Glass with Cristobalite inclusions

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chalcedony Pebble

Silicon Dioxide (SiO2)

Chert (Siliceous Mudstone variant)

Microcrystalline quartz (SiO2)

Mookaite Jasper

Radiolarite (Silicon Dioxide, SiO2)

Jasper-Agate

Silicon Dioxide (SiO2)

Yellow-brown chert or jasper pebble

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

Polished red jasper

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

Chert / Flint

Cryptocrystalline Quartz (SiO2)

Sandstone

Clastic Sedimentary Rock

Polished snowflake obsidian

Obsidian, volcanic glass (SiO₂-rich rhyolitic composition) with cristobalite spherulites

Chalcedony (possibly lavender or gray agate)

Microcrystalline quartz, SiO₂; fibrous quartz aggregate

Ocean Jasper

Orbicular Jasper (Silicon Dioxide, SiO2)

Chert (Tan/Yellow variety)

Microcrystalline quartz (SiO2)

Chert (Jasper/Flint variant)

Microcrystalline quartz (SiO2)

River Cobble (Phyllite or Quartzite)

Metasedimentary Rock (often containing SiO2 or KAl2(AlSi3O10)(OH)2)

Chert Pebble

Microcrystalline Quartz (SiO2)

Chert (Flint Nodule)

Microcrystalline Quartz (SiO2)

Quartz Geode / Druzy Quartz

Silicon Dioxide (SiO2)

Chert (Jasper / Quartz pebble)

Microcrystalline Quartz (SiO2)

Green Moss Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe)

Chert (Jasper-like Silicate)

Microcrystalline Quartz (SiO2)

Milky Quartz Geode / Chalcedony Nodule

Quartz (Silicon Dioxide - SiO2)

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide impurities

Jasper and Quartz Breccia

Silicified Breccia / Microcrystalline Quartz

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Banded Agate

Cryptocrystalline Quartz (SiO2)

Yellow Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)