Meteorite

Slag

Anthropogenic Vitrification Product / Silicate Slag

Rounded sandstone cobble

Clastic sandstone, likely quartz-rich (quartz arenite or arkose)

Iron-rich laterite or limonite/goethite specimen

Hydrated iron oxides/hydroxides, chiefly goethite (FeO(OH)) and limonite (variable FeO(OH)·nH₂O), possibly hematite (Fe₂O₃)

Fossiliferous limestone (likely ammonite/gastropod-bearing)

Bioclastic limestone; predominantly calcite (CaCO₃)

Weathered iron-rich rock, possibly limonite-bearing quartzite or altered basalt

Indeterminate; likely quartz (SiO₂) with iron oxides/hydroxides such as limonite/goethite

Small brown-gray mineral fragment

Indeterminate; possibly weathered quartz-, feldspar-, or iron-oxide-bearing rock

Tumbled dark quartzite or basalt pebble

Likely fine-grained basalt (plagioclase–pyroxene), though quartzite is possible from the image

Weathered iron-rich concretion or possible meteorite

Likely limonite/goethite concretion; meteorite status unconfirmed

Peridot

Olivine ((Mg, Fe)2SiO4)

Sandstone (with Iron Siderite Concretion)

Arenite with Ironstone Concretion (FeCO3)

Likely hematite-rich ironstone or metallic mineral fragment

Hematite (Fe₂O₃), possibly with magnetite (Fe₃O₄) or metallic iron

Dark, vesicular volcanic rock (likely basaltic scoria)

Scoria; fine-grained basaltic rock composed chiefly of plagioclase, pyroxene, and possibly olivine

Black Diamond (Carbonado)

Carbonado (Polycrystalline Diamond)

Weathered quartz-rich sandstone, possibly iron-stained quartzite

Quartz sandstone (quartz arenite), SiO₂-rich; exact identification requires hardness and texture tests

Ferruginous Sandstone (Gozzan/Ironstone)

Arenite with Limonite/Goethite cement (FeO(OH)·nH2O)

Gold Nugget

Native Gold (Au)

Gold Ore (Lode Gold)

Native Gold (Au) in Matrix

Gold Nugget

Native Gold (Au)

Industrial slag (iron/copper smelting slag)

Multiphase vitreous metallurgical slag; commonly iron-silicate glass with metal-oxide and metallic inclusions

Tektite (Indochinite)

Tektite (Silica-rich natural glass)

Blue glass-like bead or gemstone keychain ornament

Indeterminate; likely cobalt-blue glass or synthetic blue spinel, not identifiable as a natural mineral from the image

Rounded dark speckled pebble, likely basalt

Basalt; fine-grained mafic volcanic rock, typically composed of plagioclase, clinopyroxene, and iron-magnesium minerals

Likely raw garnet-bearing metamorphic rock

Garnet schist or garnet amphibolite; probable almandine garnet (Fe₃Al₂Si₃O₁₂)

Basalt pebble

Fine-grained mafic volcanic rock, typically plagioclase + clinopyroxene ± olivine and magnetite

Likely basalt (possibly iron-rich slag or meteorite mimic)

Basalt; chiefly plagioclase feldspar, pyroxene, and often olivine

Gold Nugget

Native Gold (Au)

Gold Nugget

Native Gold (Au)

Vesicular Basalt (Iron Scoria)

Aphanitic Mafic Igneous Rock with Vesicular Texture

Iron-rich concretion or weathered ironstone

Goethite–hematite limonite aggregate (FeO(OH), Fe₂O₃, and hydrated iron oxides)

Iron-rich concretion (probable limonite/goethite concretion)

Hydrated iron oxides, chiefly limonite (FeO(OH)·nH₂O) and goethite (FeO(OH))

Moldavite

Moldavite (Silica-rich glass, SiO2 + Al2O3)

Moldavite

Moldavite (Silica Glass with impurities)

Tektite (Indochinite)

Tektite (High-silica impact glass)

Tektite (Indochinite)

Tektite (High-silica impact glass)

Weathered iron-rich rock, possibly limonite-bearing basalt or ironstone

Indeterminate; likely basaltic or ferruginous rock containing iron oxides/hydroxides such as hematite (Fe₂O₃) and limonite/goethite

Likely weathered iron-rich rock or slag fragment

Indeterminate; possibly limonite/goethite-bearing rock (FeO(OH)·nH₂O) or industrial iron slag

Iron-rich chert or jasper fragment

Microcrystalline quartz (SiO₂), colored by iron oxides/hydroxides

Mica-rich granite or pegmatite fragment

Feldspar–quartz–mica rock, likely biotite granite or granitic pegmatite

Weathered granite or granitic gneiss pebble

Granite; chiefly quartz, feldspar, and mica

Likely basaltic rock fragment

Fine-grained mafic igneous rock, probably basalt (plagioclase–pyroxene ± olivine)

Likely iron-rich volcanic rock (basalt/pyroclastic fragment)

Basaltic rock, potentially weathered andesite; exact identification requires testing

Dark mafic rock, possibly basalt or meteorite-like specimen

Likely basalt (plagioclase–pyroxene assemblage); meteorite identification cannot be confirmed visually