Organic Structure (Not A Rock)

Chert (Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Veined Limestone (Micrite) with Quartz/Calcite Veins

Calcium Carbonate (CaCO3) with Silicate or Carbonate inclusions

Gneiss

High-grade regional metamorphic rock (Foliated)

Shale (Beach-worn)

Laminated Pelite (primarily clay minerals and quartz)

Chert (specifically Red Chert/Jasper variety)

Silicon Dioxide (SiO2)

Chert (often referred to as Flint)

Chert (Microcrystalline Quartz, SiO2)

Petrified Wood

Silicified Wood (SiO2)

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Amber

Succinite

Chert

Microcrystalline Quartz (SiO2)

Chert (variations include Flint/Jasper)

Chert (SiO2)

Jasper (Red Jasper)

Silicon Dioxide (SiO₂)

Chert (often called Flint for darker varieties)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Amber

Succinite (approximate formula C10H16O)

Petrified Wood

Silicified Wood (SiO2 as Quartz/Chert/Chalcedony)

Chert (with Limestone and Iron Oxide staining)

Cryptocrystalline Quartz (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Amber

Succinite (fossilized resin)

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

Amber

Succinite (a common variety of fossilized resin)

Chert

Chert (SiO2)

Amber

Succinite (specifically for Baltic amber); Chemical formula approximately C10H16O

Fossiliferous Limestone

CaCO3 (principally Calcite or Aragonite)

Glauconitic Sandstone

Glauconitic Quartz Arenite

Amber

Succinite (specifically for Baltic amber); Complex mixture of organic compounds (C10H16O)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Moss Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxides

Amber (Dark/Black Variety)

Succinite (Resinite), C10H16O

Anthracite Coal

Anthracite (Carbon-based organic sedimentary rock exposed to metamorphic heat/pressure; Chemical composition is approximately 86%–98% Carbon)

Quartz Geode

Silicon Dioxide (SiO2) within a secondary sedimentary structure

Pearl

Aragonite (CaCO3 with conchiolin)

Chert (and Flint)

Microcrystalline Silica (SiO2)

Basalt

Basalt (Mafic volcanic rock)

Chert (and/or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Fossiliferous Limestone (Coquina / Shell Limestone)

Bioclastic Limestone (CaCO3)

Chert (Limestone-based)

Silicon dioxide (SiO2)

Chert (Arrowhead Preform or Flake)

Microcrystalline Quartz (SiO2)

Chert (with Quartz vein/coating)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Banded Chert

Microcrystalline Quartz (SiO2)