Synthetic (Man Made Material Mimicking Natural Stone)

Chert (Arrowhead/Artifact Fragment)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Cubic Zirconia

Zirconium Dioxide (ZrO2)

Diamond

Diamond (pure Carbon, C)

Clear quartz crystal sphere

Quartz (silicon dioxide, SiO₂)

Pet Rock (Man-made Quartzite or Granite Cobble)

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

Blue Sapphire

Corundum (Al2O3)

Faceted Diamond or Cubic Zirconia

Carbon (C) for Diamond; Zirconium dioxide (ZrO2) for CZ

Mother of Pearl (Nacre)

Aragonite (CaCO3) with Organic Matrix

Turquoise cabochon jewelry

Turquoise, hydrated copper–aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O

Colorless faceted gemstone, likely cubic zirconia

Synthetic cubic zirconia (zirconium dioxide, ZrO₂); identity is visual and not definitive

Amethyst cabochon

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

Man-made Metal Pin (Non-geological)

Antimony-Lead Alloy or Zinc/Brass Base with Electroplating

Terrazzo (Synthetic Composite Rock)

Cementitious or Epoxy Resin-bound Aggregates

Iridescent coated quartz (likely synthetic/display gemstone)

Quartz, silicon dioxide (SiO₂), likely faceted and surface-coated; exact material cannot be confirmed visually

Coquina / Fossiliferous Limestone

Coquina (composed primarily of Calcium Carbonate / CaCO3)

Dyed Agate / Painted Stone

Silicon Dioxide (SiO2) with artificial pigment

Slag (Industrial Glass/Glassy Rock)

Anthropogenic Vitreous Material

Cullet Glass (Man-made Glass Slag)

Amorphous Silica (SiO2) with chemical additives

Rough Diamond

Pure Carbon (C)

Colorless faceted gemstone, likely cubic zirconia

Cubic zirconia (synthetic ZrO₂), possibly glass or quartz

Pearl-and-gemstone insect brooch

Pearl: nacre (aragonite, CaCO₃); colored stones are likely synthetic or natural corundum/spinel/glass, not determinable from the image

Transit Token (RTD Denver)

Nickel-plated brass or bronze alloy (Cu-Sn-Zn-Ni)

Clear quartz sphere

Quartz (silicon dioxide, SiO₂), likely rock crystal or low-grade milky quartz

Chert

Microcrystalline Quartz (SiO2)

Diamond ring

Diamond, crystalline carbon (C)

Faceted yellow gemstone, likely citrine

Citrine (quartz), SiO₂; possibly yellow sapphire or synthetic glass without testing

Red faceted gemstone jewelry setting

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

Raw quartz crystal

Quartz (silicon dioxide, SiO₂), likely milky or included quartz

Blue glass-like tumbled specimen

Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image

Ametrine

Silicon Dioxide (SiO2) with iron impurities

Diamond

Native Carbon (C)

Polished brown jasper (likely brecciated or orbicular jasper)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide and other mineral inclusions

Red Swirl Beads (Likely Resin or Glass, simulating Red Jasper or Agate)

N/A (for the beads as pictured); Red Jasper: SiO2 (Chert variety); Red Agate: SiO2 (Chalcedony variety)

Emerald in Matrix

Beryl (Be3Al2Si6O18) with trace amounts of Chromium/Vanadium

Crushed Stone / Gravel

Aggregatus saxum (variable mineral composition)

Chert (Honey Chert / Flint)

Silicon Dioxide (SiO2)

Clear Quartz (faceted) / Diamond Simulant

Silicon Dioxide (SiO2) / Cubic Zirconia (ZrO2)

Diamond

Pure Carbon (C)

Dyed Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Conglomerate

Clastic Sedimentary Rock (Conglomerate)

Picture Jasper

Silicon Dioxide (SiO2)

Blue Goldstone

Aventurine Glass (SiO2 with Co and metallic inclusions)