Antropogenic (Man Made Material)

Slag Glass

SiO2 (Silicon Dioxide) with impurities

Opalite (likely imitation opal glass)

Man-made opalescent glass; not a natural mineral (often sold as opalite)

Small greenish crystal/mineral fragment

Indeterminate; possibly olivine, quartz, or a green gemstone fragment

Slag (Industrial Glass/Metal)

Ferrous slag or Glassy silicate byproduct

Opalite (Synthetic Opalized Glass)

Synthetic Silicon Dioxide (SiO2) glass

Opalite crescent pendant

Opalite (man-made opalescent glass; not a natural mineral)

Opalite

Synthetic Opalite Glass / Opalized Glass

Carborundum (Silicon Carbide)

Silicon carbide (SiC)

Tumbled opalite (likely man-made glass)

Opalite glass; a synthetic opalescent glass, not a natural mineral species

Asphalt (Road Aggregate)

Bituminous Conglomerate / Asphalt Concrete

Obsidian (likely black volcanic glass)

Obsidian; primarily amorphous volcanic silica glass, approximately SiO₂-rich rhyolitic composition

Green Obsidian Sphere (man-made glass)

Vitreous Silica with Chromium/Iron additives

Aluminum Slag

Anthropogenic Aluminum (Al)

Tumbled milky quartz (likely)

Quartz, silicon dioxide (SiO₂)

Decorative mosaic cross containing mixed rock and glass fragments

Polychrome aggregate; likely quartz, feldspar, marble, granite, and assorted colored glass

Black glassy fragment, likely obsidian or industrial glass

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

Smelter Slag

Anthropogenic Silicate Slag

Faceted clear gemstone, likely quartz or glass imitation

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

Rounded graywacke or sandstone cobble

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

Mystic Topaz (Treated Quartz or Topaz)

Aluminum silicate fluoride hydroxide [Al2SiO4(F,OH)2] with thin-film metallic coating

Sandstone Concretion

Limonitic Sandstone Concretion

Diamond

Carbon (C)

Ferruginous Conglomerate (or Iron-Rich Concrete/Slag)

Clastic Sedimentary (Silicon Dioxide/Iron Oxide matrix)

Opalite

Synthetic Opalite (Man-made glass)

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

Green Sea Glass

Man-made silicate glass (weathered)

Polished black pebble, possibly obsidian

Volcanic glass (obsidian), likely; identification is tentative from the image

Opalite (likely man-made glass)

Opalite; amorphous silica glass, not a natural mineral

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

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

Carborundum (Silicon Carbide)

Silicon Carbide (SiC)

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Titanium-coated Metal Cube (Man-made Fidget Toy)

Titanium-anodized or electroplated alloy (e.g., Ti-coated Zinc or Aluminum)

Polished black stone, likely black obsidian

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

Milky quartz (rough fragment)

Quartz, silicon dioxide (SiO₂)

Tumbled milky chalcedony (likely common opalite-like quartz)

Chalcedony, microcrystalline SiO₂; possibly pale common opal, hydrated SiO₂·nH₂O

Opalite

Synthetic Glass (Silica-based)

Titanium Aura Quartz

Titanium bonded Silicon Dioxide (SiO2 + Ti)

Polished white chalcedony or quartz pendant

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

Metal Alloy (Likely Pewter or Sterling Silver)

Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).

Goldstone (Red)

Aventurine Glass (SiO2 + Cu)

Blue opal heart cabochon

Common opal, hydrated amorphous silica (SiO₂·nH₂O), likely blue-dyed or synthetic opalite

Clear Quartz Sphere (Rock Crystal)

Silicon Dioxide (SiO2)