Man Made Byproduct (Often Mistaken For Obsidian Or Emerald)

Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)

Obsidian Fetish Carving with Turquoise Inlay

Volcanic Glass with Turquoise (CuAl6(PO4)4(OH)8·4H2O)

Sulfur

Native Sulfur (S)

Ferruginous Quartz (Iron-stained Quartz)

Quartz with Iron Oxide inclusions (SiO2 with Fe2O3)

Serpentine

Serpentinite (group of minerals based on (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)

Quartzite Cobble

Quartzite (SiO2)

Siltstone/Sandstone (possibly Wonderstone or Picture Sandstone)

Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide inclusions)

Amethyst

Silicon dioxide (SiO2) with iron impurities

Quartzite

Metamorphic Quartzite

Dendritic Opal (Merlinite)

Hydrated Silica with Manganese/Iron oxide inclusions (SiO2·nH2O)

Dumortierite Quartz

Dumortierite (Al7BO3(SiO4)3O3 / inclusion in SiO2)

Dumortierite Quartz

Al7(BO3)(SiO4)3O3

Sandstone

Clastic Sedimentary Rock

Obsidian

Volcanic Glass (predominantly SiO2)

Chert (Jasper)

Microcrystalline Quartz (SiO2) with Iron Oxide impurities

Dendritic Limestone

Calcite with Manganese Oxide (Manganese Dendrites)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Apache Tear (Obsidian)

Obsidian / Amorphous Volcanic Glass (primarily SiO2)

Fluorite

Calcium fluoride (CaF2)

Not a geological specimen

N/A (man-made object)

Jasper

Silicon dioxide (SiO2) with impurities

Jadeite

Jadeite (NaAlSi2O6)

Anthropogenic Heat Source (Electronic/Industrial Interface)

Thermal IR emission (Electronic infrastructure)

Sandstone

Arenite (SiO2, often with CaCO3 or Fe2O3 cement)

Quartzite

Metamorphic Quartzite (SiO2)

Synthetic Convention Badge (Plastic/PVC)

Polyvinyl Chloride (PVC) / Polycarbonate

Quartz Pebble (with Manganese dendrites/staining)

Silicon Dioxide (SiO2) with Manganese Oxide impurities

Amethyst

Amethyst (Silicon Dioxide, SiO2 + Fe4+ impurities)

Apache Tear

Obsidian (Hydrated Silica / Amorphous Volcanic Glass)

Quartzite

Quartzite (Metamorphosed Sandstone)

Chert (varietal: Flint/Jasper)

Silicon Dioxide (SiO2)

Milky Quartz (Stained with Iron)

Silicon Dioxide (SiO2)

Basalt

Basalt (containing plagioclase, pyroxene, and olivine)

Basalt

Basalt

Emerald

Beryl (Be₃Al₂Si₆Oထ₈) with Chromium/Vanadium impurities

Jadeite Jade

NaAlSi2O6 (Sodium Aluminum Silicate)

Ferruginous Sandstone Concretion (Ironstone Phosphorite)

Ferruginous Sandstone (variable Fe-oxide/hydroxide composition)

Obsidian

Volcanic Glass (SiO2)

Siltstone with iron staining

Siltstone (primarily SiO2 with FeO(OH) coatings)

Diabase (Dolerite)

Diabase / Dolerite

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Siltstone or Mudstone

Siltstone (composed primarily of silt-sized particles)