Anthropogenic (Man Made Artifact)

Sea Glass (Uranium/Vaseline Glass variant)

Silicon Dioxide (SiO2) with trace Uranium Oxide (U3O8)

Chert (Arrowhead Fragment)

Cryptocrystalline quartz (SiO2)

Slag (Industrial Glass)

Anthropogenic Vitreous Slag (Post-industrial byproduct)

Cobalt Blue Slag Glass

Amorphous Silicon Dioxide (anthropogenic) with Cobalt additives

Ferrous Slag (Iron Smelting By-product)

Fused Siliceous Slag

Sea Glass (Kelly Green)

Amorphous Silica (Silicon Dioxide with Iron/Chromium additives)

Chert

Silicon dioxide (SiO2)

Chert (Flint Nodule)

Microcrystalline quartz (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Jasper variation)

Silicon Dioxide (SiO2)

Chert (Iron-Stained)

Microcrystalline Silica (SiO2)

Chert (specifically Flint or Common Chert)

Silicon Dioxide (SiO2)

Chert (Green variety)

Microcrystalline Quartz (SiO2)

Chert (Flint Arrowhead)

Microcrystalline Quartz (SiO2)

Volcanic Scoria (Metate)

Vesicular Basalt

Terrazzo (with Marble and Granite fragments)

Cementitious or resinous composite containing Calcium Carbonate (CaCO3) and Silicates

Chipped Glass/Plastic Fragment

Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic

Carved limestone architectural fragment

Limestone, predominantly calcite (CaCO₃), possibly weathered fossiliferous or oolitic limestone

Obsidian Arrowhead Replica (or similar knapped stone)

Obsidian (volcanic glass) or Chert

Chert / Flint (or lithic artifact flake)

Microcrystalline Quartz (SiO2)

Possible basaltic volcanic rock or iron-rich meteorite

Likely basalt (plagioclase–pyroxene rock); meteorite status cannot be confirmed visually

Possible tektite or iron-rich slag-like natural specimen

Uncertain; possibly natural glass (tektite) or magnetite-rich rock

Chert (Arrowhead variety)

Chert (SiO2)

Chert (often called Flint when dark or worked)

Cryptocrystalline silica (SiO2)

Dark flint or chert fragment

Microcrystalline quartz (SiO₂), likely chert/flint

Chert (Arrowhead)

Chert (primarily Microcrystalline Silica, SiO2)

Blue slag glass or dyed glass-like industrial material

Amorphous silicate glass; likely copper-bearing blue slag, but possibly colored man-made glass

Chert (Arrowhead/Projectile Point)

Microcrystalline Quartz (SiO2)

Obsidian (likely Apache tear or flaked obsidian)

Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, non-crystalline)

Worked flint/chert artifact

Microcrystalline quartz (chalcedony), SiO₂; likely a knapped flint or chert flake/core fragment

Black Chert (Flint)

Silicon Dioxide (SiO2)

Chert

Microcrystalline Quartz (SiO2)

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (specifically Flint or Jasper variant)

Microcrystalline Quartz (SiO2)

Obsidian / Chert (Arrowhead Artifact)

Obsidian (volcanic glass, SiO2 with impurities)

Chert (Flint)

Chert (Microcrystalline Quartz, SiO2)

Greenstone Celt (Polished Stone Axe)

Metamorphosed mafic rock (often Basalt or Diabase)

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Quartz Heart or Arrowhead Shape

Silicon Dioxide (SiO2)