Mineraloid (Synthetic)

Diamond (or Cut Gemstone / Cubic Zirconia)

Carbon (C)

Emerald

Beryl (Be3Al2(SiO3)6) colored by Chromium and/or Vanadium

Carborundum (Silicon Carbide)

Silicon Carbide (SiC)

Dark blue polished stone pendant

Indeterminate; possibly sodalite, lapis lazuli, or blue slag/glass-like material

Cubic Zirconia (Faceted)

Zirconium dioxide (ZrO2)

Silicon

Crystalline Silicon (Si)

Cubic Zirconia (Simulated Diamond)

Zirconium dioxide (ZrO2)

Obsidian (black volcanic glass)

Obsidian; predominantly rhyolitic volcanic glass, mainly SiO₂ with minor feldspar, quartz, and iron oxides

Likely obsidian (rough fragment)

Volcanic glass, predominantly silica-rich rhyolitic composition (SiO₂-rich, noncrystalline)

Obsidian

Volcanic Glass (Amorphous SiO2)

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Common Opal with Host Rock

Opal (Hydrated silica, SiO2·nH2O)

Mahogany Obsidian

Obsidian (volcanic glass with hematite/magnetite inclusions)

Precious Opal

Hydrated Silica (SiO2·nH2O)

Smoky Quartz

Smoky Quartz (Silicon Dioxide, SiO2)

Gold-colored gemstone ring, likely citrine or glass imitation

Indeterminate from image; possible quartz (SiO₂) or yellow glass set in gold-colored metal

Tiger’s eye

Quartz (SiO₂), fibrous pseudomorph after crocidolite

Polished amethyst cabochon

Amethyst, purple quartz (SiO₂)

Polished tiger’s eye

Quartz (microcrystalline SiO₂) with crocidolite-derived iron oxides

Larimar

Pectolite (NaCa2Si3O8(OH))

Emerald

Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities

Hematite bead bracelet

Hematite (iron(III) oxide, Fe₂O₃), likely polished magnetic hematite or hematite-coated beads

Blue glass-like gemstone, likely synthetic spinel or glass

Uncertain; possibilities include synthetic cobalt-blue spinel (MgAl₂O₄) or cobalt-colored glass

Colorless faceted gemstone, likely cubic zirconia or diamond

Uncertain from image; cubic zirconia (ZrO₂) is a common diamond simulant, while diamond is crystalline carbon (C)

Diamond ring

Diamond, crystalline carbon (C), likely colorless or near-colorless brilliant-cut stones set in gold

Small faceted gemstone, likely diamond

Diamond (crystalline carbon, C)

Colorless faceted gemstone, likely cubic zirconia

Cubic zirconia (synthetic zirconium dioxide, ZrO₂); possibly colorless quartz or laboratory diamond

Goldstone

Aventurine glass

Precious Opal

Hydrated Silicon Dioxide (SiO2·nH2O)

Faceted glass-like gemstone object

Likely synthetic glass or cubic zirconia; exact material cannot be confirmed from the image

Red faceted gemstone jewelry setting

Likely synthetic ruby or red spinel centerpiece with colorless accent stones; exact identification requires gemological testing

Ruby (Corundum)

Corundum (Aluminum Oxide with Chromium), Al2O3:Cr

Coal (Anthracite/Bituminous)

Carbo fossilium (primarily Carbon)

Diamond (or Cubic Zirconia simulant)

Carbon (C) - Diamond / Zirconium dioxide (ZrO2) - CZ

Blue Sapphire

Corundum (Al2O3 with trace Titanium and Iron)

Sandstone (likely Fossilized Wood or Concrete Simulacrum)

Arenite / Silicified Wood / Anthropogenic Concrete

Cubic Zirconia

Zirconium Dioxide (ZrO2)

Limonite (Ironstone) Concretion

FeO(OH)·nH2O (Hydrous ferric oxide)

Obsidian

Obsidian (Volcanic Glass)

Snowflake Obsidian

Volcanic Glass with Spherulite inclusions (Chemical composition: 70–75% SiO2 + MgO, Fe3O4)

Obsidian (Black Obsidian)

Obsidian (Volcanic Glass)

Diamond (Baguette cut)

Carbon (C)