Mineral Precipitate (Anthropogenic Context)

Iron-rich slag or weathered ironstone fragments

Probably hematite–goethite material; possibly industrial iron slag (Fe₂O₃/FeO(OH))

Chert (specifically a Lithic Flake)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Synthetic Faux Fur Fursuit

Polyacrylonitrile / Polyester (Synthetic Textile)

Obsidian (likely)

Volcanic glass, predominantly silica-rich rhyolitic composition (no fixed mineral formula)

Concrete / Anthropogenic Conglomerate

Man-made composite material (Portland cement, aggregate, and water)

Possible basaltic volcanic rock or iron-rich meteorite

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

Concrete fragment with Aggregate

Anthropogenic Concrete with Calcarious and Siliceous Aggregate

Synthetic Costume Accessory (Non-Geological)

Polyester and Acrylic Fiber (Anthropogenic polymer)

Slag

Anthropogenic Vitrification Product / Silicate Slag

Quartz-rich hydrothermal vein rock, possibly quartzite

Mostly SiO₂ (quartz), with probable iron oxides and minor sulfides

Polished turquoise sphere with purple matrix/inclusion

Turquoise, hydrated copper–aluminum phosphate; approximate formula CuAl₆(PO₄)₄(OH)₈·4H₂O

Chalcedony / milky quartz flake

Microcrystalline quartz (SiO₂), likely chalcedony; possibly a worked quartzite or chert fragment

Glass

Amorphous Silicon Dioxide (SiO2)

Limonite/Goethite Concretion

Goethite (FeO(OH))

Granite

Granite (phaneritic intrusive felsic igneous rock)

Chert Arrowhead

Microcrystalline Quartz (SiO2)

Hypersthene

(Mg,Fe)SiO3 - Enstatite-Ferrosilite series

Quartzite Pebble

Quartzite (SiO2)

Ferruginous Sandstone Concretion (Ironstone Phosphorite)

Ferruginous Sandstone (variable Fe-oxide/hydroxide composition)

Sandstone (Ferruginous Concretion)

Ferruginous Sandstone Concretion / SiO2 with Fe2O3 cement

Mica Schist

Mica Schist (Quartz-Mica Schist)

Chert (often called Flint)

Chert (Microcrystalline Quartz, SiO2)

Conglomerate (Asphaltic/Anthropogenic)

Clastic sedimentary rock / Bituminous mixture

Quartz-rich rock, likely milky quartz vein material

Predominantly quartz (SiO₂); exact rock type cannot be confirmed from the photograph

Slag

Glassy silicate byproduct (anthropogenic material)

Painted River Rock

Anthropogenic-modified Siliciclastic Sedimentary Rock

Ferro-slag (Leland Blue/Slag Glass)

Anthropogenic Vitreous Silica (Industrial Slag)

Yellow Ochre / Limonite

Hydrated ferric oxide (FeO(OH)·nH2O)

Chert (Arrowhead/Projectile Point)

Microcrystalline Quartz (SiO2)

Eudialyte in Matrix

Na15Ca6(Fe,Mn)3Zr3(Si,Nb)(Si25O73)(O,OH,H2O)3(Cl,OH)2

Granite pebble

Granite, a coarse-grained felsic intrusive igneous rock composed chiefly of quartz, feldspar, and mica

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Sulfidic Mudstone with Pyrite/Goethite

Sulfidic Siltstone/Mudstone (FeS2)

Chert (Arrowhead Artifact)

Microcrystalline Quartz (SiO2)

Chert Arrowhead (Lithic Artifact)

Microcrystalline Quartz (SiO2)

Chert Arrowhead (Lithic Artifact)

Chert (Cryptocrystalline Quartz, SiO2)

Chert Arrowhead

Cryptocrystalline Quartz (SiO2)

Chert (with Drusy Quartz Pocket)

Silicon Dioxide (SiO2)

Red Jasper (Mookaite style)

Silicon Dioxide (SiO2) with iron oxide impurities

Greenstone

Greenschist (metamorphosed mafic igneous rock)

Dark slate (probable)

Slate, a fine-grained metamorphic rock composed mainly of mica-group minerals and quartz; exact identification is uncertain from the photograph.

Granite Pebble

Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)