Manufactured Glass (Simulant)

Tumbled pale quartz/chalcedony fragment

Quartz (SiO₂), possibly microcrystalline chalcedony

Green iridescent glass cabochon or synthetic gemstone

Likely synthetic glass; possibly coated synthetic quartz or lab-created green gemstone

Polished black obsidian pyramid/block

Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

Costume Jewelry with Synthetic Gemstones

Synthetic Cubic Zirconia and Glass (SiO2 / ZrO2)

Small stud earring with a purple gemstone (possibly amethyst)

Possible amethyst, a purple variety of quartz (SiO₂); identification is uncertain from the image

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

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

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

Blue Sapphire

Corundum (Al2O3)

Tumbled obsidian

Volcanic glass; chiefly silica-rich rhyolitic glass (approximately 70–80% SiO₂)

Quartz

Silicon Dioxide (SiO2)

Goldstone

N/A (Synthetic Glass with Copper Inclusions)

Goldstone (blue/black aventurine glass)

Man-made aventurine glass; silica glass containing metallic copper or other glittering inclusions

Blue Goldstone

Goldstone (artificial glass)

Cullet Glass / Slag Glass

Amorphous silica glass

Blue Goldstone

Aventurine glass (Synthetic borosilicate glass with cobalt and metallic inclusions)

Vesicular volcanic rock, likely pumice

Pumice (highly vesicular volcanic glass; composition commonly rhyolitic to andesitic)

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (SiO2) with metallic oxide impurities

Tumbled granite (likely biotite granite)

Granite: quartz + feldspar + biotite/hornblende

Tumbled jasper (likely ocean/picture jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide inclusions

Milky quartz pebble

Quartz (SiO₂), likely massive or microcrystalline quartz

Gray chalcedony or quartz fragment

Microcrystalline quartz, SiO₂ (tentative)

Faceted clear gemstone pendant, likely a colorless diamond

Diamond (carbon, C); identification cannot be confirmed from the image

Small pale mineral/rock fragment

Indeterminate; possibly weathered quartz, calcite, or light-colored limestone

Blue gemstone ring, likely sapphire

Corundum, Al₂O₃ (probable blue sapphire); surrounding stones may be diamonds or simulants

Cullet Glass (Industrial Slag Glass)

Amorphous Silica (SiO2) with metallic oxide impurities

Beaded blue-and-green gemstone jewelry

Likely dyed or treated chalcedony/agate and green aventurine or glass-like stone; exact identification requires testing

Quartzite

Metamorphic Quartzite (SiO2)

Quartz fragment

Quartz (silicon dioxide, SiO₂)

Cobalt Glass Slug (Cullet)

Man-made Silicate Glass with Cobalt Oxide (CoO)

Likely obsidian (black volcanic glass)

Obsidian; predominantly rhyolitic volcanic glass, mainly SiO₂

Crackle Quartz (Dyed)

SiO2 (Silicon Dioxide) - Treated

Tumbled obsidian

Volcanic glass; chiefly SiO₂, noncrystalline

Blue glass-like cabochon, likely dyed or synthetic material

Uncertain; possibly dyed chalcedony, synthetic spinel, or blue glass

Likely polished dark stone or glassy mineral bead

Indeterminate; possibly obsidian, hematite, or a dark agate

Black Opal (Triplet)

Hydrated Silica (SiO2·nH2O)

Hematite cameo or hematine imitation

Hematite (Fe₂O₃); possibly synthetic hematine or black glass

Possibly tumbled dark stone or mineral specimen

Indeterminate from image; possibly black tourmaline, basalt, or another dark silicate

Quartzite

Metamorphic Quartzite (SiO2)

Tumbled orange calcite (probable)

Calcite, calcium carbonate (CaCO₃)

Strawberry Quartz (or Rose Quartz / Cherry Quartz)

Silicon Dioxide (SiO2) with Lepidocrocite, Hematite, or Goethite inclusions

Quartz pebble in concrete

Quartz (SiO₂), embedded in Portland-cement concrete