Mineral Precipitate (Anthropogenic Context)

Quartz geode or vuggy quartz vein fragment

Quartz (SiO₂), likely with minor iron oxides and host carbonate or silicate minerals

Angular gray rock fragments

Unidentified fine-grained rock; the image does not show diagnostic features sufficient for a specific identification

Fossilized bone or tooth fragment

Mineralized vertebrate bone; exact taxon indeterminate from image

Shale or Slate with Quartz Veins

Shale (fine-grained clastic sedimentary rock) or Slate (low-grade metamorphic rock formed from shale) with Quartz (SiO2) veins

Sandstone (Water-worn Cobble)

Arenite (variable composition, primarily SiO2)

Black Jasper

Silicon dioxide (SiO2) with carbon/mineral inclusions

Chert (Arrowhead Preform or Point)

Chert (Microcrystalline Quartz, SiO2)

Native American Pottery Sherd

Sodium Polyacrylate (Superabsorbent Polymer)

Sodium Polyacrylate [-CH2-CH(COONa)-]n

Quartz crystal cluster (likely druzy quartz)

Quartz, silicon dioxide (SiO₂)

Blue Dyed Quartzite

Silicon Dioxide (SiO2) with artificial pigment

Terrazzo (Synthetic Composite Rock)

Cementitious or Epoxy Resin-bound Aggregates

Stromatolite (stromatolitic limestone)

Laminated microbial carbonate, chiefly calcite (CaCO₃); precise species or age cannot be determined from the photo

Lepidolite

K(Li,Al)3(Al,Si,3O10)(F,OH)2

Mystic Topaz

Aluminum silicate fluoride hydroxide with titanium coating (Al2SiO4(F,OH)2)

Cupronickel (on a 1981 Mexico 20 Pesos coin)

Copper-Nickel Alloy (Cu75Ni25)

Iron-rich slag or ironstone; appearance is not diagnostic

Likely iron-oxide-rich material (hematite, Fe₂O₃, and/or magnetite, Fe₃O₄); possibly smelting slag

Red obsidian (likely mahogany obsidian)

Volcanic glass; primarily silica-rich rhyolitic glass (SiO₂), commonly with iron-oxide inclusions

Green Moonstone (Garnierite)

Nickel-bearing Magnesium Silicate (often a mix of Serpentine and Talc/Chlorite groups)

Hematite (Tumbled)

Iron(III) oxide (Fe2O3)

Concrete Fragment

Artificial Conglomerate (Cement and Aggregate)

Amethyst (rough crystal)

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

Black Jasper

Black Jasper (Silicate mineral - SiO2)

Sea Glass (Frosted Glass Fragment)

Amorphous Silica (Anthropogenic Sediment)

Leland Blue Stone

Anthropogenic Iron Smelting Slag

Slag (Industrial Byproduct)

Anthropogenic Vitreous Silicate material

Slag

Anthropogenic Vitreous Silica/Iron oxides

Asphalt (Bituminous Concrete)

Asphaltum / Bitumen-Aggregate Matrix

Iron-Nickel Meteorite fragment

Siderite (meteoritic iron), composed primarily of Kamacite (α-(Fe,Ni)) and Taenite (γ-(Fe,Ni))

Native gold nugget or flake

Native gold (Au), possibly with minor silver/electrum

Gold Nugget

Native Gold (Au)

Mixed rock specimens; likely pink feldspar/quartz and a dark, mica-bearing rock

Tentative visual identification: pink K-feldspar–quartz-rich granite/pegmatite fragments and a dark amphibole- or biotite-rich metamorphic rock; exact identification is uncertain from the image

Likely weathered metallic mineral or slag fragment

Uncertain; possibly limonite/goethite-coated iron mineral, or industrial iron slag

Milky Quartz Pebble with Iron Inclusions

Silicon Dioxide (SiO2) with iron oxide impurities

Shale with Pyrite

Clastic sedimentary rock containing Iron Disulfide (FeS2)

Fossilized shell fragment

Likely a fossil mollusk shell; exact taxon cannot be determined from the image

Slag (Industrial Glass)

Anthropogenic Amorphous Vitreous Silicate

Lava Rock with Fabric Impression

Scoria or Basalt with anthropogenic impressions

Iron Slag

Anthropogenic Vitreous Ferrous Silicate

Asphalt Chunk (with aggregate)

Bituminous concrete / Anthropogenic conglomerate

Blue Sea Glass

Amorphous Silica (Anthropogenic glass)

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions