Man Made Object (Metalwork)

Blue glassy fragment among beach gravel

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

Opalite

Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)

Slag Glass (Cullet)

Amorphous Silica (man-made), primarily SiO2 with trace metal oxides

Carved Stone Turtle

Mixed stone carving

Aventurine

Quartz containing inclusions of Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Ferro-silicate Slag

Industrial Vitrified Slag (High-silica amorphous glass)

Man-made Glass (Tumbled/Shaped)

Amorphous Silicon Dioxide (SiO2) with metal oxide colorants

Man-made Slag (Industrial Byproduct)

Anthropogenic Glassy Residue

Man-made Dyed Aura Quartz

Silicon Dioxide (SiO2) with metallic coating/dye

Purple glassy pebble, possibly slag glass

Unidentified; likely man-made glass rather than a natural mineral

Green sea glass (likely slag glass or bottle glass)

Man-made soda-lime silicate glass; not a naturally occurring mineral

Green Sea Glass

Amorphous Silica (man-made glass), SiO2 + additive metal oxides

Chalcedony (likely agate)

Microcrystalline quartz, SiO₂; agate is banded chalcedony

Clear faceted gemstone in a gold-colored setting

Likely colorless quartz (rock crystal) or synthetic cubic zirconia; visual identification is inconclusive

Tumbled black obsidian (likely)

Volcanic glass; chiefly silica-rich rhyolitic glass (SiO₂)

Slag Glass (Leland Blue variant)

Anthropogenic Vitreous Silicate

Smelter Slag

Anthropogenic Silicate Slag

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Brown chert (flint)

Microcrystalline quartz (SiO₂), commonly called chert; “flint” is a dark variety

Chipped Glass/Plastic Fragment

Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic

Tumbled blue chalcedony (possibly blue agate)

Microcrystalline quartz, SiO₂; chalcedony variety

Libyan Desert Glass

Impact-melt silica glass (SiO2 + traces of Al, Fe, Ti)

Blue chalcedony cabochon (likely)

Chalcedony, microcrystalline SiO₂; possibly blue agate or common opal, which cannot be distinguished confidently from the image

Chert (flint), brown variety

Microcrystalline quartz (SiO₂)

Small dark pebble, likely basalt or iron-rich rock

Uncertain from image; possibly fine-grained basalt (mafic silicate rock)

Fossil coral

Fossilized colonial coral, likely rugose or tabulate coral preserved in limestone

Tumbled milky chalcedony (likely common opal or quartz-rich chalcedony)

Chalcedony, microcrystalline SiO₂; identification is uncertain from the photo

Tumbled yellow chalcedony (possibly citrine or pale agate)

Chalcedony, microcrystalline quartz (SiO₂); exact variety cannot be confirmed visually

Polished stromatolite (likely fossilized microbial mat)

Fossil stromatolite; chiefly microcrystalline quartz (SiO₂), commonly replacing carbonate

Green Aventurine

Aventurine Quartz (SiO2 with Fuchsite inclusions)

Turquoise ring

Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; the setting appears to be silver-colored metal

Dark green cabochon gemstone ring

Unknown; possibly green onyx (cryptocrystalline quartz, SiO₂) or another green gem

Goldstone (aventurine glass)

Man-made copper-bearing glass; not a natural mineral (commonly sold as blue/brown goldstone)

Possible yellow agate or chalcedony bead

Microcrystalline quartz (SiO₂), likely chalcedony; identification is uncertain from the photo

Painted Rock / Geode Specimen

Silicon Dioxide with artificial pigment coating

Red agate bead (likely dyed or treated)

Agate, a microcrystalline variety of quartz; SiO₂

Tumbled chalcedony pendant (likely agate)

Chalcedony, microcrystalline quartz (SiO₂); the pale bands suggest agate

Dyed Crackle Quartz

Silicon Dioxide (SiO2) with synthetic dye

Red jasper (likely)

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored red by iron oxides

Goldstone

N/A (Synthetic Glass with Copper Inclusions)

Chert (likely flint)

Microcrystalline quartz, SiO₂