Organic Material (Likely A Fruit Or Berry)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Chert (and Flint)

Silicon dioxide (SiO2) - Microcrystalline quartz

Blue Sphalerite (likely dyed or treated Druzy Quartz/Agate)

Zinc Sulfide (ZnS) or Silicon Dioxide (SiO2) with trade-name enhancement

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Not a geological specimen

N/A (man-made object)

Chert (Iron-stained or Dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Flint nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Fossilized Shark Tooth (Fragment)

Elasmobranchii fossil (likely Cretalamna or Squalicorax genus)

Granite with Epidote

Granite, containing quartz, feldspar, and epidote

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified Wood (primarily SiO₂ - Silicon Dioxide)

Petrified Wood

Silicified Wood (SiO2)

Chert (and Jasper/Flint variant)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline silicon dioxide (SiO2)

Chert / Flint Nodules

Chert (Cryptocrystalline variety of Quartz, SiO2)

Fossiliferous Sedimentary Rock (Coquina/Limestone)

Fossiliferous Calcarenite / Bioclastic Limestone

Sandstone

Arenite (primarily composed of SiO2)

Calligraphy Stone

Mariam Jasper (Fossiliferous Limestone with Hematite and Iron)

Chert (Flint variety)

Silicon Dioxide (SiO2)

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (varietal Chalcedony or Flint)

Silicon dioxide (SiO2) - Microcrystalline Quartz

Chert (often called Flint)

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2)

Blue Lace Agate (with Amethyst Geode center)

Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony

Jasper / Chert (River Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Yellow Jasper)

Microcrystalline Quartz (SiO2)

Chert (often called Flint in various colors)

Silicon Dioxide (SiO2)

Chert (variations include Flint/Jasper)

Chert (SiO2)

Sandstone

Arenite (primarily SiO2)

Sandstone (with banding/weathering)

Clastic Sedimentary Rock (primarily SiO2)

Rhyolitic Tuff (Breccia Type)

Rhyolitic Pyroclastic Rock (Mixed Silicates including Quartz, Feldspar, and Volcanic Glass)

Sandstone (Quartz-rich)

Clastic sedimentary rock (SiO2 primary)

Sandstone (likely Quartzose)

Sandstone (Principally SiO2)

Sandstone (likely Arkosic)

Arenite (SiO2 with KAlSi3O8)

Chert (and/or Chalcedony)

Microcrystalline Silica (SiO2)

Chert (variations include Flint)

Chert (Silicon Dioxide, SiO2)

Man-made Carved Stone (Scream Mask/Skull motif)

Carved Soapstone or Serpentine-rich rock

Quartz (specifically Milky/Gray Quartz vein)

Silicon Dioxide (SiO2)

Sandstone

Arenite (primarily SiO2)

Asphalt (Bituminous Concrete)

Composite material (bitumen binder with mineral aggregate)