Anthropic Metallic Specimen

Pyrite

Iron Sulfide (FeS2)

Man-made earbud charging case (Not a rock or mineral)

Acrylonitrile Butadiene Styrene (ABS) Plastic with electronic components

Basalt

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Basalt (River Stone)

Extrusive mafic igneous rock

Likely galena-bearing ore

Galena (lead sulfide, PbS), possibly mixed with quartz or other sulfides

Graphite-rich schist (probable)

Graphite schist; primarily graphite (C) with mica and quartz

Moqui Marble

Iron Oxide Concretion (Limonite/Hematite shell with Sandstone core)

Pyrite (“fool’s gold”)

Iron disulfide, FeS₂; cubic isometric sulfide mineral

Quartz-rich breccia or vein quartz specimen

Microcrystalline and crystalline quartz (SiO₂), possibly with iron-oxide staining and minor sulfides

Fluorite

Calcium Fluoride (CaF2)

Galena

Galena (lead sulfide, PbS)

Iron Meteorite / Chondrite (Possible)

Extraterrestrial stony-iron or chondritic meteorite

Fluorite

Calcium Fluoride (CaF2)

Arfvedsonite in Quartz

Arfvedsonite [Na3(Fe2+4Fe3+)Si8O22(OH)2] often hosted in Quartz or Feldspar

Fluorite

Calcium fluoride, CaF2

Basalt Pebble

Basalt (Extrusive Igneous Rock)

Small dark metallic-looking rock fragment

Undetermined; possibly iron oxide-rich material or a metallic mineral

Likely magnetite (small rough crystal)

Magnetite, Fe₃O₄

Quartz-rich hydrothermal vein rock, possibly quartzite

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

Metallic sulfide-bearing ore, likely pyrite-rich rock

Pyrite (FeS₂), possibly mixed with quartz or other sulfides

Possible iron-rich stone or meteorite fragment

Undetermined; possibly magnetite-bearing rock or an ordinary chondrite

Likely metallic meteorite fragment

Unclassified iron-rich meteorite; possible stony-iron or iron meteorite

Galena

Lead Sulfide (PbS)

Purple fluorite cluster with metallic sulfide inclusions

Fluorite, calcium fluoride (CaF₂), likely with pyrite or chalcopyrite inclusions

Basalt

Basalt (dominated by Plagioclase and Pyroxene)

Amazonite

Amazonite (KAlSi3O8)

Quartz with Metallic Inclusion

Silicon Dioxide (SiO2) with associated metallic sulfide or oxide

Pyrite

Iron Sulfide (FeS2)

Copper Ore

Cupriferous Rock / Mixed Mineral Matrix

Muscovite Mica

KAl2(AlSi3O10)(OH)2

Limonite (with goethite)

Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)

Iron-rich quartzite or silicified ironstone

Quartz (SiO₂) with iron oxides/hydroxides, likely limonite/goethite and possibly hematite

Iridescent bismuth crystal

Bismuth (Bi), commonly laboratory-grown and oxidized

Basalt (River Pebble)

Extrusive Mafic Igneous Rock

Basalt

Basalt

Iridescent polished/tumbled stone (likely coated quartz or glassy synthetic material)

Indeterminate; possibly quartz (SiO₂) with an artificial iridescent coating

Goethite–limonite ironstone (iron-rich laterite)

Hydrated iron oxides, chiefly goethite FeO(OH) and limonite (variable mixture)

Gold Nugget

Native Gold (Au)

Labradorite

(Ca, Na)(Al, Si)4O8 (Calcium Sodium Aluminum Silicate)

Chalcopyrite

Copper iron sulfide (CuFeS2)

Mica Schist with Vein

Mica Schist

Iron-rich hematite/goethite concretion (likely limonite)

Hematite (Fe₂O₃) with goethite (FeO(OH)) and limonite