Anthropogenic (Man Made)

Milky quartz (likely)

Quartz, silicon dioxide (SiO₂)

Tumbled black stone, likely black obsidian

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

Concrete-like aggregate surface with embedded rock fragments

Anthropogenic concrete or exposed aggregate; not a natural rock specimen

White pebble, likely quartz or calcite

Indeterminate from image; possible microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Polished blue glassy mineral specimen, likely sodalite or blue aventurine

Most consistent with sodalite (Na₈Al₆Si₆O₂₄Cl₂), though dyed quartzite or blue glass cannot be excluded from the photograph

Cubic Zirconia (Jewelry Setting)

Zirconium Dioxide (ZrO2)

Diamond

Native Carbon (C)

Conglomerate

Conglomerate (clastic sedimentary rock)

Blue glassy gemstone-like specimen

Indeterminate; possibly dyed or treated turquoise, blue apatite, or man-made glass

Red glassy gemstone, possibly garnet

Unidentified red transparent material; garnet group (X₃Y₂(SiO₄)₃) is a possibility

Blue Goldstone

Synthetic glass with cobalt and copper inclusions

Cubic Zirconia (Jewelry Setting)

Cubic Zirconia (ZrO2)

Dzi Bead (Etched Chalcedony)

Cryptocrystalline Quartz (SiO2) with chemical etching

Dragon's Breath (Mexican Opal Glass)

Artisan Foil Glass (SiO2 based)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Sea Glass

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

Polished opalite (likely man-made opalescent glass)

Opalite is a commercial name, not a mineral; typically opalescent glass, often soda-lime silicate glass

Sea Glass

Man-made silicate glass (Amorphous silicon dioxide)

Terracotta (Man-made ceramic brick fragment)

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

Likely tumbled red mineral or glass imitation

Indeterminate; possibilities include red jasper (microcrystalline quartz, SiO₂) or dyed chalcedony

Quartz crystal fragment (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

Dalmatian Stone

Dalmatian Jasper (a misnomer for an Aplite with Arfvedsonite spots)

Small rounded mineral pebble, possibly quartz

Uncertain; likely microcrystalline or crystalline SiO₂ (quartz), potentially with iron-oxide staining

Titanium Aura Quartz

Silicon Dioxide (SiO2) coated with Titanium and Niobium

Concretion with Geode Cavity

Ferruginous Sandstone Concretion with Quartz Center

Concrete fragment or Conglomerate

Artificial Conglomerate (Concrete) or Natural Conglomerate

Sea Glass

Man-made vitreous material (silica-based glass)

Sea Glass

Man-made vitreous material (silica glass)

Goldstone

Man-made glass infused with metallic copper

Opalite

Man-made Glass (Synthetic Opalized Glass)

Opalite

Synthetic Glass / Man-made Opal Simulant

Goldstone

Avventurina (Man-made Glass with Copper inclusions)

Opalite

Synthetic Opalized Glass / Man-made Glass

Opalite

Man-made glass (traditionally simulated Opal)

Tumbled milky quartz

Quartz (SiO₂), cryptocrystalline-to-massive variety

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂), opaque-to-translucent milky variety

Goldstone

Man-made glass infused with copper crystals

Blue Sandstone

Man-made glass with cobalt and copper inclusions

Goldstone

Man-made glass containing cuprous oxide

Goldstone

Man-made glass infused with copper particles

Opalite-style glass pendant

Man-made opalescent glass (not natural opal)

Blue opalite glass cabochon (likely imitation opal)

Man-made opalescent glass; not a natural mineral