Antropogenic (Man Made)

Faceted clear gemstone, likely quartz or glass imitation

Most likely quartz (SiO₂); exact identification requires refractive-index and hardness tests

Black tumbled stone, possibly obsidian

Obsidian (volcanic glass; predominantly SiO₂), identification uncertain from image

Rounded graywacke or sandstone cobble

Lithified clastic sandstone; likely quartz–feldspar–lithic grain aggregate in a silica or calcite matrix

Clear quartz crystal (likely)

Quartz, silicon dioxide (SiO₂)

Polished dendritic agate or jasper

Microcrystalline quartz (SiO₂), likely chalcedony with iron/manganese dendrites

Fluorite (Polished Point/Tower)

Calcium Fluoride (CaF2)

Possible obsidian or slag glass

Volcanic glass, primarily SiO₂; alternatively industrial iron-rich glassy slag

Goldstone (Red)

Aventurine Glass (Cupriferous glass)

Clear quartz tumbled stone

Quartz (silicon dioxide, SiO₂)

Aura Quartz

Titanium-coated Silicon Dioxide (SiO2)

Concrete with Aggregate

Composite construction material; primary matrix is Calcium Silicate Hydrate (C-S-H)

Ferrochrome Slag

Anthropogenic slag (Fe-Cr alloy waste)

Cubic Zirconia (Simulated Diamond)

Cubic Zirconia (ZrO2)

Opalite

Synthetic Opalized Glass

Opalite

Synthetic Opalite Glass (Silicon Dioxide)

Blue Glass or Slag Glass

Amorphous Silica (Anthropogenic Glass)

Blue-dyed tumbled quartz or glass imitation

Quartz (SiO₂), appearance possibly enhanced with blue dye; identity uncertain from image

Sea Glass

Amorphous silicon dioxide (SiO2) - Man-made glass tumbled by nature

Ferruginous Conglomerate (or Iron-Rich Concrete/Slag)

Clastic Sedimentary (Silicon Dioxide/Iron Oxide matrix)

Blue Goldstone

Man-made glass with suspended copper, cobalt, or manganese particles

Black glassy fragment, likely obsidian or industrial glass

Volcanic glass (obsidian), chiefly amorphous SiO₂; identification uncertain from image

Milky quartz (likely quartz crystal fragment)

Quartz, silicon dioxide (SiO₂)

Smelter Slag

Anthropogenic Silicate Slag

Quartz crystal (likely clear quartz)

Quartz, silicon dioxide (SiO₂)

Polished gemstone tower assortment

Primarily quartz varieties and simulants; apparent amethyst (SiO₂), rose quartz (SiO₂), clear quartz (SiO₂), fluorite (CaF₂), sodalite, malachite, and possibly dyed or composite stones

Polished black stone, likely black obsidian

Obsidian (volcanic glass), chiefly silica-rich rhyolitic composition

Sandstone Anvil / Nutting Stone

Quartzose Sandstone (Sedimentary Rock)

Pink Tumbled Quartz (Dyed)

Silicon Dioxide (SiO2)

Dyed Crackle Quartz (Green)

Quenching-treated Quartz (Silicon Dioxide, SiO2)

Quartzite (Engineered Stone)

Silicon Dioxide (SiO2) based synthetic composite

Chert Concretion (with typical hematite/limonite staining)

Sedimentary Concretion (SiO2 with FeO(OH)⋅nH2O)

Sandstone Concretion

Clastic Sedimentary Rock (primarily SiO2 with mineral cement)

Pyrite Concretion (Grapestone)

Iron Sulfide (FeS2) Concretion

Slag Glass

SiO2 (Silicon Dioxide) with impurities

Opalite

Synthetic Glass, SiO2 base with metallic inclusions

Tumbled gray stone, likely quartz-rich pebble

Probable microcrystalline quartz/chalcedony (SiO₂), possibly gray jasper or quartzite

Goldstone (Brown/Gold variety)

Aventurine Glass (SiO2 with Copper inclusions)

Blue Goldstone

Goldstone (artificial glass)

Pet Rock (Man-made Quartzite or Granite Cobble)

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

Black Obsidian

Amorphous volcanic glass (SiO2 + impurities)

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Green obsidian (likely molded or heat-treated glass-like specimen)

Volcanic glass; predominantly rhyolitic composition (silica-rich amorphous SiO₂)