Man Made Material (Constructed)

Aura Quartz

Titanium-coated Silicon Dioxide (SiO2)

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

Opalite (Synthetic Opalized Glass)

Synthetic Silicon Dioxide (SiO2) glass

Ceramic or Polished Stone Heart (Anthropogenic Material)

Glazed Ceramic (Silicon Dioxide based coating on Alumina Silicate body) or Polished Limestone/Marble (Calcium Carbonate, CaCO3)

Opalite crescent pendant

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

Iron Slag (Industrial Byproduct)

Anthropogenic Vitrification Product/Ferrous Slag

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

Travertine

Terrestrial Sedimentary Limestone (CaCO3)

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

Travertine

Calcium Carbonate (CaCO3)

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

Faceted clear gemstone, likely quartz or glass imitation

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

Travertine (or Calcareous Tufa)

Calcium Carbonate (CaCO3)

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)

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