Anthropogenic Specimen (Man Made Material)

Carborundum (Silicon Carbide)

Silicon Carbide (SiC) / Moissanite (natural form)

Green Glass (often marketed as 'Obsidian' or 'Green Quartz')

Amorphous Silica (SiO2) with copper or chromium additives

Conglomeratic gravel / polymictic breccia

Polymictic rudite, likely anthropogenic or beach/stream gravel; composition varies

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Terrazzo (with Marble and Granite fragments)

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

Polished blue-green glassy slag or coated mineral fragment

Most likely man-made colored glass/slag; exact composition cannot be determined visually

Polished green-and-black banded cabochon (likely malachite imitation or dyed agate)

Uncertain; possible malachite (Cu₂CO₃(OH)₂), banded agate (SiO₂), or man-made glass

Banded Slag Glass (Leland Blue/Frankfort Green style)

Anthropogenic Glass Specimen (Amorphous Silicon Dioxide with impurities)

Chert Nodule (Flint)

Chert (Silicon Dioxide, SiO2)

Dyed Blue Agate (Dragon Vein Agate)

Silicon Dioxide (SiO2) with artificial cobalt/organic dyes

Granite with Cupules / Bedrock Mortars

Granite (felsic intrusive plutonic rock)

Red coral (likely precious coral)

Corallium sp.; calcium-carbonate skeleton, primarily calcite

Amber-set ring

Amber (fossilized plant resin; organic mineraloid), set in a metal ring

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

Chert / Jasper

Silicon Dioxide (SiO₂)

Slag (Industrial By-product)

Anthropogenic Vitreous Silica/Iron Silicate

Opalite

Synthetic glass (SiO2 + metal additions)

Slag (Industrial Byproduct)

Ferro-silicate glass (Slag)

Raw quartz crystal

Quartz (silicon dioxide, SiO₂), likely milky or included quartz

Sandstone

Arenite (SiO2 based clastic rock)

Blue-green chrysocolla rough specimen

Chrysocolla, hydrated copper aluminosilicate; commonly associated with malachite, quartz, and limonite

Mother of Pearl (Nacre) / Shell Fragment

Biogenic Calcium Carbonate (Aragonite and Conchiolin)

Weathered iron-rich rock, possibly jasper or ironstone

Likely limonite/goethite-bearing siliceous rock; exact identification requires hardness and streak tests

Chert (specifically Jasper or Flint)

Cryptocrystalline Quartz (SiO2)

Concrete or asphalt-like aggregate surface with a dark fragment

Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock

Iron Slag

Ferrous slag (primarily silicates and oxides of calcium, iron, and magnesium)

Banded Chert (River Stone)

Silicon Dioxide (SiO2)

Asphalt (Bituminous Pavement Bit)

Bitumen-bound aggregate (Petrochemical-bound composite)

Asphalt (Bituminous Concrete)

Composite material (bitumen binder with mineral aggregate)

Fulgarite

Fulgurite (Lechatelierite / Vitrified Sand)

Metallic sulfide mineral fragment, likely galena

Galena (lead sulfide, PbS), tentative identification

Chert (Arrowheads)

Microcrystalline Quartz (SiO2)

Opalite

Synthetic Opalised Glass

Chert Arrowhead

Cryptocrystalline Quartz (SiO2)

Chert (Polished River Pebble)

Chert (SiO2)

Colorless faceted gemstone, likely quartz

Quartz (SiO₂), tentative identification; the photo is insufficient to confirm the material

Chert (Arrowhead or Flake)

Microcrystalline quartz (SiO2)

Tumbled brown chalcedony or jasper

Microcrystalline quartz, SiO₂; possibly iron-bearing jasper

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Quartzite Arrowhead (Archaeological Lithic)

Recrystallized Quartz (SiO2)

Polished/tumbled brown-and-white mineral fragment

Indeterminate; possibly quartz-rich jasper, brecciated jasper, or an iron-stained quartz mineral