Man Made Byproduct (Often Mistaken For Obsidian Or Emerald)

Obsidian

Volcanic glass (SiO2-rich amorphous silicate)

Obsidian

Obsidian (Volcanic Glass, SiO2)

Obsidian

Amorphous Volcanic Glass (primarily SiO2)

Limestone Concretion (Botryoidal/Calcareous Nodules)

Calcium Carbonate Concretion (CaCO3)

Emerald

Beryl (Be3Al2Si6O18 with chromium and vanadium impurities)

Jasper (Multi-colored) / Sea Glass Slag

Silicon Dioxide (SiO2) with impurities of Iron Oxide

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Obsidian

Volcanic glass (high silica volcanic rock)

Obsidian

Obsidian

Dendritic Rhodonite

Rhodonite (Manganese Silicate), (Mn,Fe,Mg,Ca)SiO3

Emerald

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

Blue Dumortierite Quartz

Dumortierite in Quartz (AlAl6BSi3O12(O,OH)3)

Sandstone

Arenite (specifically sublithic or quartz arenite)

Quartzite River Rock with Dendrites

Metamorphosed Quartz-rich Sandstone with Manganese Oxide (MnO2) inclusions

Tumbled mahogany obsidian

Volcanic glass, predominantly rhyolitic silica (SiO₂), with iron-oxide inclusions

Obsidian (likely snowflake or banded variety)

Volcanic glass, primarily SiO₂

Emerald

Beryl (Be3Al2(SiO3)6)

Quartzite

Metamorphic Quartzite (SiO2)

Rough Diamond (or Quartz Crystal)

Carbon (C) [if Diamond] / Silicon Dioxide (SiO2) [if Quartz]

Chert (flint) fragment

Microcrystalline quartz (SiO₂), commonly called chert; “flint” is a variety of chert

Quartzite

Quartzite (composed primarily of Quartz, SiO2)

Chert (Chert / Flint)

Microcrystalline Quartz (SiO2)

Chert (Nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Green faceted gemstone earrings, likely synthetic emerald-colored glass or cubic zirconia

Undetermined; possible glass (amorphous silicate) or synthetic cubic zirconia (ZrO₂)

Howlite

Howlite, Ca₂B₅SiO₉(OH)₅

Obsidian

Volcanic Glass (predominantly SiO2)

Polished black obsidian

Volcanic glass; primarily rhyolitic SiO₂, with minor iron, magnesium, and other trace elements

Quartzite Pebble

Quartzite (SiO2 with minor impurities)

Obsidian

Volcanic Glass (SiO2 rich)

Obsidian

Volcanic glass; chiefly rhyolitic silica glass (SiO₂-rich, commonly ~70–80% SiO₂)

Satin Spar (Gypsum)

Calcium Sulfate Dihydrate (CaSO4·2H2O)

Diamond

Carbon (C)

Obsidian

Volcanic Glass (70% or more SiO2)

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide)

Opalite

Man-made opalized glass

Sandstone

Sedimentary Rock (Quartz arenite)

Metal Chain Belt with Square Plates

Not applicable (man-made)

Obsidian

Volcanic Glass (SiO2)

Banded Sandstone Peabble

Arenite with iron oxide banding

Quartzite Pebble (Yellow/Cloudy Quartz)

Silicon Dioxide (SiO2) - Recrystallized Sandstone

Peridot

Olivine (Mg, Fe)2SiO4

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurity)