Anthropogenic (Man Made Material Mimicking Sedimentary Rock)

Slate

Metamorphic Pelitic Rock

Polished black stone, likely black obsidian

Obsidian (volcanic glass), chiefly silica-rich rhyolitic composition

Chert (Flint)

SiO2 (Microcrystalline Quartz)

Chert (Flint)

Silicon Dioxide (SiO2)

Flint

Silicon dioxide (SiO2)

Blue Impression Jasper beads

Impression jasper (microcrystalline quartz/chalcedony), chiefly SiO₂, with iron-oxide and other mineral inclusions

Chert Nodule

Microcrystalline Quartz (SiO2)

Sandstone (likely Fossiliferous)

Arenite / Fossiliferous Sandstone (SiO2 composition)

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Weathered concrete or cementitious slab (not natural rock)

Artificial calcium-silicate cement composite; likely Portland cement concrete

Possible obsidian or slag glass

Volcanic glass, primarily SiO₂; alternatively industrial iron-rich glassy slag

Obsidian (likely black volcanic glass)

Obsidian; primarily amorphous volcanic silica glass, approximately SiO₂-rich rhyolitic composition

Sandstone

Arenite (siliciclastic sedimentary rock composed mostly of quartz)

Small greenish crystal/mineral fragment

Indeterminate; possibly olivine, quartz, or a green gemstone fragment

Pyrite Concretion (Grapestone)

Iron Sulfide (FeS2) Concretion

Man-made Metal Pin (Non-geological)

Antimony-Lead Alloy or Zinc/Brass Base with Electroplating

Chert (Chert / Flint)

Microcrystalline Quartz (SiO2)

Carborundum (Silicon Carbide)

Silicon Carbide (SiC)

Coquina (Fossiliferous Limestone)

Biogenic Limestone (Calcium Carbonate, CaCO3)

Concrete or asphalt-like aggregate surface with a dark fragment

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

Chert Arrowhead

Microcrystalline Quartz (SiO2)

Green glass cabochon or tumbled stone

Indeterminate; likely man-made glass, possibly aventurine glass rather than a natural mineral

Chert (and Agate/Chalcedony)

Microcrystalline Quartz (SiO2)

Sandstone

Arenite

Slag

Anthropogenic Vitrophyre (Iron or Smelting Slag)

Mixed beach-stone and tumbled-glass collection

Predominantly uncertain rocks (likely basalt, granite, and quartz-bearing stones) with anthropogenic glass; one possible banded agate or jasper

Tumbled clear quartz (rock crystal)

Quartz, silicon dioxide (SiO₂)

Chert Arrowhead

Microcrystalline Quartz (SiO2)

Polished dendritic agate or jasper

Microcrystalline quartz (SiO₂), likely chalcedony with iron/manganese dendrites

Polished gemstone tower assortment

Primarily quartz varieties and simulants; apparent amethyst (SiO₂), rose quartz (SiO₂), clear quartz (SiO₂), fluorite (CaF₂), sodalite, malachite, and possibly dyed or composite stones

Asphalt (Bituminous Concrete)

Asphaltum / Bitumen-Aggregate Matrix

Blue Goldstone

Goldstone (artificial glass)

Faceted clear gemstone, likely quartz or glass imitation

Most likely quartz (SiO₂); exact identification requires refractive-index and hardness tests

Possible tektite or iron-rich slag-like natural specimen

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

Chalk

Carbonate rock (mainly CaCO3)

Slag Glass (Cullet)

Amorphous Silicon Dioxide (SiO2) with metal oxide colorants

Opalite (Man-made Glass)

Synthetic Silicon Dioxide Glass (SiO2 + metal oxides)

Cullet (Slag Glass)

Amorphous Silica (Industrial byproduct)

Vesicular basalt (probable iron-rich volcanic rock)

Basalt; chiefly plagioclase, clinopyroxene, olivine, and Fe-Ti oxides

Painted River Pebble (likely Basalt or Greywacke)

Aphanitic Lithic Clast with Anthropogenic Pigment coating

Chert (Flint)

Microcrystalline quartz (SiO2)

Sandstone

Arenite