Mineral Precipitate (Anthropogenic Context)

Reddish-brown, iron-stained rock fragment

Indeterminate; possibly weathered porphyritic volcanic rock

Pyrite-bearing quartz vein (likely pyrite ore)

Pyrite, FeS₂, with abundant quartz (SiO₂) and possibly chalcopyrite

Iron Slag

Anthropogenic Iron oxide/Silicate composite

Fossilized shell or small fossil fragment

Indeterminate fossil; possibly a partial gastropod or bivalve, mineralized with calcite

Rounded gray stone, likely quartz-rich granitic rock

Probable granite or granitic gneiss; mainly quartz, feldspar, and mica

Cobaltian Calcite (Cobaltoan Calcite)

Cobalt-bearing Calcite (Ca,Co)CO3

Painted River Pebble (likely Basalt or Greywacke)

Aphanitic Lithic Clast with Anthropogenic Pigment coating

Orange glassy slag (industrial by-product)

Iron-rich silicate glass; composition varies, commonly Fe–Ca–Al silicate

Blue-gray kyanite crystal

Kyanite (Al₂SiO₅)

Weathered gray stone, likely granite or gneiss

Probable granitic rock; exact identification is uncertain from the image

Titanium Aura Quartz (Bismuth-coated Druzy)

Silicon Dioxide (SiO2) with Titanium/Metal vapor coating

Red Sandstone

Arenite (primarily composed of SiO2 with Fe2O3 cement)

Dark granitic gneiss or fine-grained granite

Biotite granite, possibly weakly foliated gneiss; quartz–feldspar–biotite assemblage

Flint (chert) hand axe

Cryptocrystalline silica (SiO₂), worked into a bifacial stone tool

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

Jasper Marble

Silicon Dioxide (SiO2) with Impurities

Limonite-pseudomorph after Pyrite (Prophecy Stone)

Goethite and Limonite secondary minerals (FeO(OH)·nH2O) replacing Pyrite (FeS2)

Yellow Jasper

Chalcedony (SiO2) with iron oxide inclusions

Tumbled amethyst

Amethyst, purple quartz (SiO₂)

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial byproduct)

Chert (Cream Variety)

Microcrystalline silica (SiO2)

Quartz-rich pegmatite, possibly with mica

Granite/pegmatite composed mainly of quartz (SiO₂), feldspar, and likely biotite or muscovite mica

Leopard Skin Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Ferrochrome Slag

Anthropogenic slag (Fe-Cr alloy waste)

Dark weathered pebble, likely basalt

Basalt (fine-grained mafic volcanic rock; commonly plagioclase, pyroxene, and iron oxides)

Chert Arrowhead

Cryptocrystalline Quartz (SiO2)

Likely milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Black obsidian arrowhead

Obsidian; volcanic glass, typically rhyolitic in composition (mostly SiO₂)

Coprolite

Fossilized Feces

Possible tektite or iron-rich slag-like natural specimen

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

Possible tektite or volcanic glass specimen

Natural silica glass; composition commonly near SiO₂, but exact identification requires chemical testing

Granite Thin Section

Granitic rock (Phaneritic texture)

Small pale stone, possibly quartz or limestone

Indeterminate from image; likely quartz (SiO₂) or calcite-rich limestone (CaCO₃)

Artisanal Glass Beads (Simulated Goldstone or Aventurine Glass)

Silicon Dioxide (SiO2) with metallic inclusions

Sandstone Concretion

Limonitic Sandstone Concretion

Rose quartz

Quartz (SiO₂), pink variety

Black Tourmaline (Schorl)

Schorl (Complex sodium iron aluminum borosilicate)

Ironstone Concretion (Limonite/Goethite)

Ferruginous Sandstone or Limonite (FeO(OH)·nH2O)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Fossilized cylindrical shell or bone fragment

Indeterminate biogenic carbonate or phosphatic fossil; possible fragment of a tubular shell (e.g., scaphopod) or hollow bone

Granite

Granite (Phaneritic igneous rock)

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)