Anthropogenic (Man Made Material Processed By Nature)

Red cabochon gemstone ring (likely glass or synthetic stone)

Undetermined; the image does not establish a natural mineral identity

Chert Arrowhead

Microcrystalline Quartz (SiO2)

N/A - Man-made object (Jewelry Chain)

Antiqued or Oxidized Metal Chain (often Steel or Brass)

Tumbled milky chalcedony (likely common opalite-like quartz)

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

Sandstone Concretion

Limonitic Sandstone Concretion

Titanium Coated Aura Quartz (Apple Aura Quartz)

Silicon Dioxide (SiO2) with Metallic Vapor Deposition Coating

Chert (Arrowheads)

Microcrystalline Quartz (SiO2)

Granite with Cupules / Bedrock Mortars

Granite (felsic intrusive plutonic rock)

Titanium Amethyst Geode

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

Blue opal heart cabochon

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

Green Aura Quartz (Titanium treated Kyanite or Quartz)

Silicon Dioxide (SiO2) or Aluminum Silicate (Al2SiO5) with Titanium/Metal Oxide coating

Slag (Industrial Byproduct)

Anthropogenic Vitreous Silicate material

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

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

Opalite

Synthetic Glass (Simulated Opal)

Opalite

Synthetic Glass (Simulated Opal)

Sandstone Concretion

Clastic sedimentary rock (primarily Quartz SiO2)

Opalite

Synthetic Opalite (Man-made glass)

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

Green Sea Glass

Man-made silicate glass (weathered)

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

Terracotta (Man-made ceramic brick fragment)

Baked clay / High-iron ceramic (Silicate-based ceramic)

Luminous Stone (Glow-in-the-dark Synthetic/Man-made Stone)

Strontium Aluminate tinted glass or resin (Crystalline silicate/oxide mix)

Clear quartz fragment (rock crystal)

Quartz, silicon dioxide (SiO₂)

Polished black stone, likely black obsidian

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

Opalite (Synthetic Moonstone/Opal)

Synthetic Silica Glass

Polished white chalcedony or quartz pendant

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

Sandstone Pebble

Arenite (Siliclastic sedimentary rock)

Carborundum (Silicon Carbide)

Silicon Carbide (SiC) / Moissanite (natural form)

Milky quartz (rough fragment)

Quartz, silicon dioxide (SiO₂)

Blue glassy fragment among beach gravel

Likely cobalt-blue man-made glass; not a natural mineral specimen

Concretion (Sandstone)

Carbonate-cemented Sandstone Concretion

Blue Crackle Quartz (Dyed Quarzite)

Silicon Dioxide (SiO2) with artificial dye

Blue Goldstone

Aventurine Glass (Silicon Dioxide with metal inclusions)

Botryoidal chalcedony (likely agate/jasper variety)

Microcrystalline quartz, SiO₂

Clear Quartz Sphere (Rock Crystal)

Silicon Dioxide (SiO2)

Red-orange jasper pebble (tentative)

Microcrystalline quartz, SiO₂, colored mainly by iron oxides

Opalite Egg

Synthetic Glass (Simulated Opal)

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)

Man-made Blank Ammunition (Brass)

CuZn (Cartridge Brass - roughly 70% Copper, 30% Zinc)

Polished obsidian

Volcanic glass; predominantly rhyolitic SiO₂

Blue chalcedony (likely dyed or treated)

Microcrystalline quartz, SiO₂ (chalcedony)

Coquina

Bioclastic Limestone (composed primarily of CaCO3)