Man Made Byproduct (Often Mistaken For Obsidian Or Emerald)

Chert (with Manganese Dendrites)

Chert (Cryptocrystalline Quartz, SiO2)

Sea Glass

Man-made silicate glass

Black obsidian (likely)

Volcanic glass; predominantly silica-rich, non-crystalline silicate glass

Fluorite (Purple Fluorite Egg)

Fluorite (Calcium Fluoride, CaF2)

Ironstone Concretion (Coprolite-like)

Goethite/Hematite Siderite Spheroid (FeCO3 or FeO(OH))

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

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

Yellow Jade

Jadeite or Nephrite (NaAlSi2O6 or Ca2(Mg,Fe)5Si8O22(OH)2)

Limestone

Calcareous sedimentary rock (CaCO3)

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide)

Sandstone

Clastic Sedimentary Rock

Obsidian

Obsidian (Volcanic Glass, SiO2)

Quartzite

Quartzite

Obsidian

Obsidian

Red Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Sandstone

Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)

Pink Orthoclase Feldspar with Dendrites

Orthoclase (KAlSi3O8) with Manganese Oxide dendrites

Quartzite

Metamorphosed Quartz Sandstone

Quartzite

Quartzite (Metamorphic Quartz Sandstone)

Note on Image Identification: Textile

N/A (Anthropogenic material)

Quartzite

Silicon Dioxide (SiO2)

Sea Glass

Man-made vitreous material

Obsidian

Obsidian (Volcanic Glass)

Sandstone with Dendritic Manganese Oxides

Sandstone (SiO2 predominant) with Oxide Dendrites (MnO2)

Black stone bead bracelet

Likely black tourmaline (schorl), though identification is uncertain from the image

Banded Iron Formation

Banded Iron Formation (BIF)

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Pink Marble

Recrystallized Limestone (Calcium Carbonate, CaCO3)

Tiffany Stone

Bertrandite Fluorite (CaF2 + Be4Si2O7(OH)2)

Blue Dumortierite Quartz

AlAl6BSi3O18 (Dumortierite) within SiO2 (Quartz)

Quartzite

Quartzite (primarily SiO2)

Obsidian

Volcanic Glass (predominantly SiO2, approximately 70% or more)

Jasper with Manganese Dendrites

Silicon Dioxide (SiO2) with Oxide Mineral Inclusions

Rough Sodalite

Sodalite, Na8(Al6Si6O24)Cl2

Sandstone (likely Quartzose Sandstone)

Arenite

Chert (Flint)

Silicon Dioxide (SiO2)

Silver Nuggets (Natural or Cast)

Native Silver (Ag)

Pebble (likely Quartz or Chert)

SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.

Polished black stone bead, possibly black obsidian

Likely obsidian (natural volcanic glass; composition chiefly silica-rich volcanic glass), but identification is uncertain from the image

Calcite

Calcium Carbonate (CaCO3)

Sandstone

Arenite

Quartzite

Quartzite (primarily SiO2)