Mineraloid (Synthetic)

Limonite (Iron-rich Siltstone / Sandstone base)

Hydrous ferric oxide mixture (FeO(OH)·nH2O)

Obsidian

Volcanic glass (high silica volcanic rock)

Obsidian

Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)

Black Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Snowflake Obsidian

Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)

Obsidian

Obsidian (Volcanic Glass), primarily SiO2

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Limonite (Iron Ore Congcretion)

Limonite (a mixture of hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)

Emerald (cut gemstone)

Beryl, Be₃Al₂Si₆O₁₈, colored green mainly by chromium and/or vanadium

Imitation or Cultured Pearl Earrings

Calcium carbonate (CaCO3) or synthetic polymer/glass

Ametrine

SiO2 (Silicon Dioxide with iron impurities)

Painted Rock

Rock coated with synthetic acrylic paint

Orgonite Pyramid (containing Amethyst and mixed minerals)

Silicon Dioxide (SiO2) in synthetic resin

Opalite

Synthetic Glass (Simulated Moonstone/Opal)

Sedimentary Rock with Crafts (Pet Rock)

Sedimentary rock decorated with synthetic materials

Blue Quartz / Glass Gemstone Pendant

SiO2 (Silicon Dioxide) or Synthetic Glass

Opalite

Synthetic Opalite (Man-made glass)

Pink Dyed Agate

Silicon Dioxide (SiO2) with synthetic pigment

Dyed Quartzite

Metamorphosed Quartz (SiO2) with synthetic pigment

Dyed Crackle Quartz

Silicon Dioxide (SiO2) with synthetic dye

Opalite (Synthetic Opalized Glass)

Synthetic Silicon Dioxide (SiO2) glass

Goldstone

N/A (Synthetic Glass with Copper Inclusions)

Dyed Agate

Silicon Dioxide (SiO2) with synthetic dyes

Silicon Carbide (Carborundum)

Moissanite (SiC), though mostly synthetic

Ruby (rough or poorly polished corundum)

Corundum, Al₂O₃; red gem-quality corundum is ruby

Blue sapphire (rough corundum)

Corundum, Al₂O₃; blue color commonly from trace iron and titanium

Colorless cut gemstone, likely white sapphire

Corundum (Al₂O₃), tentatively identified; the image alone cannot confirm the stone

Blue cabochon ring stone, likely sapphire or synthetic blue corundum

Corundum (Al₂O₃), possibly chromium/iron-titanium-bearing sapphire

Corundum (Pink Sapphire / Ruby)

Al2O3 (Aluminum Oxide)

Emerald-and-diamond ring

Emerald: beryl, Be₃Al₂(SiO₃)₆, colored by chromium and/or vanadium; surrounding stones appear to be diamonds: carbon

Yellow faceted gemstone, likely citrine or yellow beryl

Quartz (SiO₂), if citrine; beryl (Be₃Al₂Si₆O₁₈), if heliodor

Lapis Lazuli

Lazurite-dominated metamorphic rock ((Na,Ca)8(AlSiO4)6(SO4,S,Cl)2)

Costume Jewelry Gemstones (Emerald-imitation and semi-precious beads)

BeCuAl6Si6O18 (Beryl structure), frequently simulated by glass or synthetic spinel

Bouncy Ball (Synthetic Rubber Polymer)

Polybutadiene / Ethylene Vinyl Acetate (EVA)

Synthetic opal cabochon/bead

Opal-like hydrated amorphous silica; likely lab-created polymer–silica opal or Gilson synthetic opal (SiO₂·nH₂O)

Zirconia (Ceramic) & Ion-X Glass

Zirconium Dioxide (ZrO2) and Ion-strengthened Aluminosilicate Glass

Diamond (or Clear Quartz / Cubic Zirconia)

Carbon (C) or Silicon Dioxide (SiO2) / Cubic Zirconia (ZrO2)

Fire Opal (in Matrix)

Hydrated Silica (SiO2·nH2O)

Faceted red gemstone, likely ruby

Corundum (Al₂O₃), colored red by chromium; identity cannot be confirmed from the image alone

Oil Shale

Kerogen-rich marlstone

Likely blue sapphire ring

Corundum (Al₂O₃), likely sapphire; surrounding stones may be diamonds or colored gems

Milky Quartz

Silicon Dioxide (SiO2)