Industrial Byproduct

Gold and Diamond

Native Gold (Au) and Diamond (C)

Quartz Pebble

Silicon Dioxide (SiO2)

Vesicular Basalt

Basalt (Mafic volcanic rock)

Sapphire Rough (Corundum)

Corundum (Aluminum Oxide, Al2O3)

Bauxite

Hydrated Aluminum Oxides (primarily Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Diaspore α-AlO(OH))

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Chert (and Jasper/Chalcedony mixture)

Microcrystalline Quartz (SiO2)

Ruby (Raw Corundum)

Corundum (Al2O3) with Chromium traces

Diamond

Carbon (C)

Blue Sapphire

Corundum (Al2O3) with traces of Iron and Titanium

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic volcanic rock; commonly basalt (plagioclase, pyroxene, and possible olivine)

Ironstone (Limonitic/Hematitic Sandstone)

Ferruginous sandstone (predominantly Fe2O3 and FeO(OH))

Diamond

C (Native Carbon)

Bornite

Bornite (Cu5FeS4)

Diamond (Cut Specimen)

Carbon (C)

Green glassy slag or manufactured glass bead

Noncrystalline silicate glass; likely industrial glass/slag, not a true mineral

Opalite

Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)

Quartzite (Engineered Stone)

Silicon Dioxide (SiO2) based synthetic composite

Quartzite

Quartzite (SiO2)

Engineerged Quartz (Quartz Composite)

SiO2 (Silicon Dioxide) in a polymer resin matrix

Opalite

Man-made Glass (Synthetic Opalized Glass)

Acrylic or Resin (Synthetic Imitation)

Polymethyl Methacrylate (PMMA) or Polyepoxide

Limestone (specifically Crushed Limestone/Calcictic)

Calcium Carbonate (CaCO3)

Asphalt (Road Aggregate)

Bituminous Conglomerate / Asphalt Concrete

Cupronickel (on a 1981 Mexico 20 Pesos coin)

Copper-Nickel Alloy (Cu75Ni25)

Quartzite

Quartzite (SiO2)

Iron meteorite (probable)

Fe–Ni metallic meteorite, commonly kamacite–taenite

Silicon Carbide (Carborundum)

Silicon Carbide (SiC)

Native copper (probable copper-rich mineral specimen)

Copper, Cu; possibly mixed with cuprite, malachite, and iron-oxide alteration minerals

Iron-rich meteorite candidate

Possibly an iron meteorite or stony-iron meteorite; unverified Fe–Ni alloy

Iron-rich vesicular rock, possibly slag or basalt

Uncertain; likely basaltic rock (plagioclase–pyroxene–iron oxide) or industrial iron slag

Diamond

Diamond (pure Carbon, C)

Polished ocean jasper (orbicular jasper), probable

Microcrystalline quartz (SiO₂) with iron-oxide and other mineral inclusions

Tumbled yellow chalcedony (likely honey agate or yellow jasper)

Microcrystalline quartz, SiO₂; precise identification is uncertain from the photograph

Indeterminate metallic mineral fragments

Possibly pyrite, chalcopyrite, or metallic sulfide-bearing rock

Tumbled blue-green stone, likely aventurine or serpentine

Quartz-rich aventurine (SiO₂) or serpentine-group mineral; exact identification requires testing

Small red-brown mineral or rock fragment

Unidentified; possibly iron-oxide-rich jasper, garnet, or weathered sulfide

Dyed blue tumbled stone, likely howlite or magnesite

Howlite (Ca₂B₅SiO₉(OH)₅) or magnesite (MgCO₃), artificially dyed blue

Uncertain polished mineral specimen

Indeterminate; possibly quartz or feldspar with iron-oxide staining

Weathered quartz-bearing rock fragment

Indeterminate; likely quartz-rich granite or silicified host rock with iron-oxide staining

Polished red jasper or mahogany obsidian (likely jasper)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Likely petrified wood or silicified fossil fragment

Silicified wood; predominantly microcrystalline quartz (SiO₂)