Organic Material (Likely A Fruit Or Berry)

Banded agate (likely carnelian/chalcedony)

Microcrystalline quartz, SiO₂; iron-stained chalcedony

Chert (often called Flint or Jasper)

Chert (Microcrystalline or Cryptocrystalline Silica, SiO2)

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Amber

Fossilized Tree Resin (C10H16O)

Rounded granitic pebble

Granite, likely biotite granite or granodiorite

Weathered fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃)

Chert (Flint)

Chert (Cryptocrystalline Silicon Dioxide, SiO2)

Chert (specifically Black Chert or Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Flint Nodules)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Graphite

Graphite (Native Carbon, C)

Chert (Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Likely quartz-rich metamorphic rock (quartzite or quartz-veined schist)

Quartzite/siliceous schist; chiefly quartz (SiO₂), with probable mica and iron-oxide staining

Dark river pebble, likely basalt or fine-grained volcanic rock

Basalt (probable); mostly plagioclase and pyroxene, with possible magnetite

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert Pebble

Microcrystalline Quartz (SiO2)

Granite pebble

Coarse-grained felsic intrusive igneous rock; mainly quartz, alkali feldspar, plagioclase, and minor biotite or amphibole

Chert Pebble

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Yellow chalcedony (likely citrine or iron-stained quartz)

Microcrystalline quartz, SiO₂; yellow coloration likely from iron oxides or included quartz varieties

Chert (Jasper)

Cryptocrystalline Quartz (SiO2)

Weathered granite or granitic gneiss fragment

Coarse quartz–feldspar–mica aggregate; possibly weakly foliated gneiss

Chert (and Flint)

Silicon dioxide (SiO2) - Microcrystalline or Cryptocrystalline Quartz

Greenstone (likely serpentinite or chlorite-rich metamorphic rock)

Probable serpentinite/chlorite schist; commonly dominated by serpentine-group minerals, chlorite, talc, and magnetite

Chert (Common Jasper)

Microcrystalline Quartz (SiO2)

Engraved polished dark stone (likely slate or basalt)

Probable fine-grained slate (microcrystalline phyllosilicates), possibly basalt; exact identification requires testing

Quartzite Pebble

Quartzite (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Sandstone (likely Arkose)

Arenite (Feldspathic Sandstone / Arkose)

Sandstone (likely Quartzose)

Arenite (primarily SiO2)

Chert / Flint (with quartz or calcite inclusion)

Silicon dioxide (SiO2)

Chert (Cherty Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Weathered sandstone or iron-stained siltstone

Quartz-rich clastic sedimentary rock, likely ferruginous sandstone

Amber

Succinite

Chert (Nodule)

Silicon Dioxide (SiO2)

Quartzite Pebble

Quartzite (primarily SiO2)

Petrified Wood

Silicified Wood (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (often called Flint)

Chert (Cryptocrystalline Quartz, SiO2)

Faceted yellow gemstone, likely citrine

Citrine (quartz), SiO₂; possibly yellow sapphire or synthetic glass without testing

Quartz-rich granite or pegmatitic rock

Granite/pegmatite; chiefly quartz (SiO₂), feldspar, and minor mica

Sandstone (likely Graywacke or Arkose variant)

Clastic Sedimentary Rock (SiO2 based)