Industrial Byproduct (Anthropogenic Rock Like Material)

Quartz Geode

Silicon Dioxide (SiO2)

Polished pietersite cabochon

Pietersite (brecciated fibrous quartz/chalcedony, commonly with riebeckite or crocidolite remnants)

Anthracite Coal

Anthracite (Carbon-rich metamorphic rock)

Sea Shell Fragment (Calcium Carbonate)

Aragonite / Calcite (CaCO3)

Synthetic Resin Charm (Seal Shape)

Polymer Resin with plastic glitter / Polyethylene terephthalate glitters

Silver (Morgan Dollar)

Native Silver (Ag) - 90% Silver, 10% Copper alloy

Quartz Pebble (Iron-Stained)

Crystalline Silicon Dioxide (SiO2)

Rutilated Quartz

Quartz (SiO2) with Rutile (TiO2) inclusions

Greenish metamorphic rock (possibly chlorite schist)

Chlorite-rich schist; exact identification is uncertain from the image

Iron-rich meteorite candidate

Unclassified meteoritic iron–stone material; possible stony-iron meteorite or terrestrial ironstone

Quartzite Pebble

Quartzite (SiO2)

Pumice

Pumicite

Sandstone

Arenite (SiO2 based)

Quartz Pebble

Silicon Dioxide (SiO2)

Chert (Quartz Pebble)

Silicon Dioxide (SiO2)

Sandstone

Sandstone (clastic sedimentary rock)

Chert (Flint/Jasper variety)

Microcrystalline Quartz (SiO2)

Granite Gravel (Pebble)

Intrusive Felsic Igneous Rock

South Korean 100 Won Coin (Cupronickel)

Cupronickel Alloy (75% Cu, 25% Ni)

Sandstone

Arenite (SiO2, often with CaCO3 or Fe2O3 cement)

Quartz-veined weathered host rock

Quartz (SiO₂) in a likely altered limestone or metamorphic carbonate host

Tektite (likely indochinite)

Natural silica-rich impact glass; predominantly amorphous SiO₂ with aluminum, iron, magnesium, calcium, and sodium

Unidentified brown rock fragment

Indeterminate from image; likely a weathered iron-rich lithic fragment

Likely weathered metallic mineral or slag fragment

Indeterminate; possibly iron-rich sulfide/oxide material or industrial slag

Diamond (or Diamond Simulant/Cubic Zirconia)

Carbon (C) - if diamond, or Zirconium dioxide (ZrO2) - if Cubic Zirconia

Quartzite Arrowhead (Archaeological Lithic)

Recrystallized Quartz (SiO2)

Sandstone

Arenite (SiO2 principal composition)

Synthetic Sapphire and Ion-X Glass

Single-crystal Alumina (Al2O3) and Ion-strengthened Aluminosilicate Glass

Weathered brown rock fragment, possibly iron-rich sandstone or altered basalt

Indeterminate; likely an iron-oxide–stained silicate rock

Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartzite

Quartzite (SiO2)

Weathered stone nodule or concretion

Unidentified lithic concretion; composition cannot be determined from the image

Quartzite

Quartzite (primarily SiO2)

Ruby / Pink Sapphire

Corundum (Al2O3 with Chromium impurities)

Red Sandstone

Sandstone (hematitic/iron-rich quartzite or arenite)

Sandstone or Mudstone

Sedimentary Rock

Polished dark stone, likely basalt or fine-grained mafic rock

Basalt (approximately; commonly plagioclase, pyroxene, and minor olivine/magnetite)

Pet Rock (Man-made Quartzite or Granite Cobble)

Silicon dioxide (SiO2) mixture; commonly composed of Quartz, Feldspar, and Mica

Sandstone

Arenite (composed primarily of SiO2)

Fossilized wood (petrified wood)

Silicified wood; commonly quartz/chalcedony (SiO₂) replacing wood tissue

Star sapphire ring

Corundum (Al₂O₃), likely asteriated sapphire

Weathered iron-rich rock fragment

Likely limonite/goethite with hematite and iron-bearing silicates; exact identification requires testing