Anthropogenic (Man Made)

Botryoidal chalcedony (likely agate/jasper variety)

Microcrystalline quartz, SiO₂

Polished silver sheen obsidian heart

Obsidian (volcanic glass), primarily rhyolitic silica-rich glass

Opalite

Synthetic Opalised Glass

Carborundum (Silicon Carbide)

Silicon Carbide (SiC)

Man-made Jewelry (Metal and Glass/Plastic)

Synthetic Alloy and Amorphous Solid (SiO2/Polymer)

Red-orange cabochon, likely carnelian or glass imitation

Carnelian: chalcedony (microcrystalline SiO₂), commonly iron-colored

Polished black pebble, possibly obsidian

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

Vesicular basalt (weathered scoria)

Scoriaceous basalt; chiefly plagioclase, clinopyroxene, olivine, and iron-titanium oxides

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Titanium Amethyst Geode

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

Green Glass (often marketed as 'Obsidian' or 'Green Quartz')

Amorphous Silica (SiO2) with copper or chromium additives

Blue-green cabochon, likely chalcedony or treated glass imitation

Cryptocrystalline quartz (chalcedony/possibly chrysoprase); identification uncertain from image

Blue Obsidian

Volcanic Glass (SiO2 with inclusions)

Green glass sphere/marble

Soda-lime glass (primarily SiO2, Na2O, CaO)

Green sea glass (likely bottle glass)

Man-made soda–lime silicate glass; not a natural mineral

Sea Glass

Amorphous silicon dioxide (Man-made glass weathered by nature)

Blue glassy tumbled stone, likely blue chalcedony or slag glass

Chalcedony (microcrystalline SiO₂), possibly man-made blue glass

Green sea glass (likely bottle glass)

Man-made soda-lime silicate glass; not a natural mineral

Milky quartz (rough fragment)

Quartz, silicon dioxide (SiO₂)

Rock crystal (clear quartz), possibly cloudy quartz

Quartz, silicon dioxide (SiO₂)

Hematite

Iron(III) oxide (Fe2O3)

Goldstone (Red)

Aventurine Glass (SiO2 + Cu)

Blue Crackle Quartz (Dyed Quarzite)

Silicon Dioxide (SiO2) with artificial dye

Dyed Blue Agate (Dragon Vein Agate)

Silicon Dioxide (SiO2) with artificial cobalt/organic dyes

Diamond

Native Carbon (C)

Dyed Aura Quartz

Silicon Dioxide (SiO2) with metallic coating

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

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

Granite with Cupules / Bedrock Mortars

Granite (felsic intrusive plutonic rock)

Red-orange jasper pebble (tentative)

Microcrystalline quartz, SiO₂, colored mainly by iron oxides

Blue chalcedony (likely dyed or treated)

Microcrystalline quartz, SiO₂ (chalcedony)

Blue Obsidian (Cullet Glass)

Silicon Dioxide (Amorphous Glass)

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)

Tumbled milky chalcedony (likely common opalite-like quartz)

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

Colorless quartz crystal (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Raw quartz crystal

Quartz (silicon dioxide, SiO₂), likely milky or included quartz

Carborundum

Silicon Carbide (SiC)

Opalite

Synthetic Opalised Glass

Carborundum (Silicon Carbide)

Silicon Carbide (SiC) / Moissanite (natural form)

Metallic sulfide mineral fragment, likely galena

Galena (lead sulfide, PbS), tentative identification

Obsidian (likely black volcanic glass)

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

Cullet (Slag Glass)

Amorphous Silica (Industrial byproduct)