Weathered iron-rich concretion or ironstone nodule
Goethite–hematite limonite concretion (FeO(OH), Fe₂O₃, and hydrated iron oxides)
sedimentary
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Mother of Pearl (Nacre)
Aragonite (CaCO3) with Organic Matrix
mineral
Diamond in Kimberlite
Diamond (C in Kimberlite)
igneous
Ceramic or Polished Stone Heart (Anthropogenic Material)
Glazed Ceramic (Silicon Dioxide based coating on Alumina Silicate body) or Polished Limestone/Marble (Calcium Carbonate, CaCO3)
Synthetic/Anthropogenic Mineraloid
Aura Quartz
Titanium-coated Silicon Dioxide (SiO2)
mineral
Opalite
Synthetic Opalized Glass (SiO2 + additives)
mineraloid (man-made)
Sea Glass (specifically Frosted White)
Amorphous Silica (substance: Sodium-calcium silicate glass)
Mineraloid (Anthropogenic/Man-made rock)
Banded Calcite
CaCO3
sedimentary
Opalite (Man-made Glass)
Synthetic Silicon Dioxide Glass (SiO2 + metal oxides)
Synthetic Mineral Simulant / Glass
Blue glassy gemstone cabochon, likely dyed chalcedony or glass
Uncertain; possible dyed chalcedony (microcrystalline quartz, SiO₂)
gemstone
Opalite (likely man-made glass)
Opalite; amorphous silica glass, not a natural mineral
gemstone
Tumbled milky quartz (likely)
Quartz, silicon dioxide (SiO₂)
mineral
Diamond
Carbon (C)
gemstone
Milky quartz (likely rough quartz crystal)
Quartz, silicon dioxide (SiO₂)
mineral
Aura Quartz (Pink/Rose Aura Quartz)
Silicon Dioxide (SiO2) bonded with Platinum and/or Silver
mineral
Aqua Aura Quartz
Titanium/Gold-coated Silicon Dioxide (SiO2)
mineral
Carborundum (Silicon Carbide)
Silicon carbide (SiC)
mineral
Dyed Agate / Painted Stone
Silicon Dioxide (SiO2) with artificial pigment
sedimentary (base), then artificial
Cultured Marble (Synthetic)
Polymer-matrix composite (typically calcium carbonate in polyester resin)
Synthetic / Composite Material
Opalite
Synthetic Fluorescent Glass (SiO2 + impurities)
mineraloid (synthetic)
Carborundum (Silicon Carbide)
Silicon Carbide (SiC)
mineral
Opalite
Synthetically produced glass (Silicon Dioxide with metallic inclusions)
Mineraloid (Man-made Glass)
Vesicular basalt (probable iron-rich volcanic rock)
Basalt; chiefly plagioclase, clinopyroxene, olivine, and Fe-Ti oxides
igneous
White quartz pebble
Quartz (SiO₂), likely milky quartz
mineral
Fossil shark tooth in sediment
Likely fossilized shark tooth, possibly *Carcharhinus* or *Otodus*; exact identification requires the tooth’s full morphology and locality
fossil
Opalite (Synthetic Opalized Glass)
Synthetic Silicon Dioxide (SiO2) glass
mineral
Greenstone / serpentinite carving
Serpentinite, chiefly serpentine-group minerals (antigorite, lizardite, or chrysotile); exact identification requires testing
metamorphic
Fossilized sea urchin
Echinoid test, likely a regular sea urchin; calcite (CaCO₃)
fossil
Opalite
Synthetic Glass (Simulated Opal)
mineral
Tumbled quartz pebble
Quartz, silicon dioxide (SiO₂), likely milky quartz
mineral
Small greenish crystal/mineral fragment
Indeterminate; possibly olivine, quartz, or a green gemstone fragment
mineral
Pyrite in Quartz (Drill Core)
Silicon Dioxide (SiO2) with Iron Sulfide (FeS2) inclusions
igneous/metamorphic (hydrothermal)
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial byproduct)
mineraloid
Ferrous Slag
Iron/Steel Slag (Complex Calcium-Alumino-Silicates)
Anthropgenic (Industrial Byproduct)
Aura Quartz (Rainbow Quartz)
Silicon Dioxide (SiO2) with metallic vapor coatings
mineral
Sandstone Concretion
Septarian or Carbonate-cemented Sandstone Concretion
sedimentary
Opalite
Synthetic opalescent glass
glass
Asphalt (Bituminous Pavement)
Bituminous mix (Aggregates with Bitumen binder)
sedimentary
Aqua Aura Quartz
Silicon Dioxide (SiO2) bonded with Gold (Au)
mineral (treated)
Glass
Amorphous Silicon Dioxide (SiO2)
mineraloid
Goldstone
Aventurine glass
mineral (man-made glass)
Green glass-like mineral specimen, likely fluorite
Fluorite (calcium fluoride, CaF₂), if natural; appearance may also indicate colored glass
mineral