Man Made

Polymictic conglomerate or breccia (possibly concrete-like aggregate)

Lithified polymictic gravel; clasts may include basalt, granite, quartzite, and other silicates

Opalite

Synthetic glass (SiO2 + metal additions)

Opalite

Synthetic Opalised Glass

Carborundum (Silicon Carbide)

Silicon Carbide (SiC)

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

Agate and millefiori glass jewelry

Agate: microcrystalline quartz (SiO₂); millefiori element appears to be man-made glass

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

Aura Quartz (Titanium/Gold coated)

Silicon Dioxide (SiO2) with metallic vapor deposition

Polished white chalcedony or quartz pendant

Microcrystalline quartz (chalcedony), SiO₂; exact identification is uncertain from the image

Iron Slag

Iron/Steel Slag (Ferrosilicate Glass)

Iron Slag (Industrial Byproduct)

Anthropogenic Vitrification Product/Ferrous Slag

Goldstone (likely red/brown aventurine glass)

Man-made aventurine glass; copper-bearing silicate glass (not a natural mineral)

Dyed or synthetic turquoise-blue glass-like specimen

Likely man-made colored glass or resin; exact identification requires testing

Blue goldstone

Man-made aventurine glass containing metallic copper particles; not a natural mineral

Likely polished quartz or glass-like mineral cabochon

Probably quartz (SiO₂), though the image cannot exclude man-made glass

Man-made Green Quartz (Lab-grown or Treated)

Silicon Dioxide (SiO2) with artificial coloration

Possible sea glass (naturally frosted glass), not a confirmed geological specimen

Man-made silicate glass; composition varies, commonly soda-lime glass

Blue glassy mineral specimen, possibly dyed or synthetic

Uncertain; possible blue fluorite (CaF₂), dyed chalcedony, or man-made glass

Ferruginous Conglomerate (or Iron-Rich Concrete/Slag)

Clastic Sedimentary (Silicon Dioxide/Iron Oxide matrix)

Goldstone (Red)

Aventurine Glass (SiO2 + Cu)

Ferro-slag (Leland Blue/Slag Glass)

Anthropogenic Vitreous Silica (Industrial Slag)

Polished black stone, likely obsidian

Obsidian (volcanic glass; mostly silica-rich rhyolitic composition)

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)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Titanium Amethyst Geode

Silicon Dioxide (SiO2) with Titanium/Metal Vapor Deposition Layer

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Conglomerate

Conglomerate Rock (Paraconglomerate)

Sandstone Concretion

Clastic sedimentary rock (primarily Quartz SiO2)

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)

Slag

Ferrous Slag (Amorphous calcium-magnesium-aluminum silicates)

Carborundum

Silicon Carbide (SiC)