Manufactured Glass

Borosilicate Glass (Manufactured)

SiO2 + B2O3 (Silicon dioxide and Boron trioxide)

Blue Obsidian

Obsidian

Green glassy slag or manufactured glass bead

Noncrystalline silicate glass; likely industrial glass/slag, not a true mineral

Fluorescent glassy mineral specimen, possibly hyalite opal

Hyalite (hydrated amorphous silica, SiO₂·nH₂O), tentative

Opalite-style glass pendant

Man-made opalescent glass (not natural opal)

Sea Glass

Silica (SiO2) - Amorphous

Sea Glass

Amorphous silicon dioxide (glass)

Black obsidian (likely)

Volcanic glass; predominantly silica-rich, non-crystalline silicate glass

Goldstone

N/A (Synthetic Glass with Copper Inclusions)

Purple glassy pebble, possibly slag glass

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

Sea Glass

Amorphous Silicon Dioxide (SiO2)

Possibly tumbled black stone (uncertain; may be black glass or obsidian)

Undetermined; possible obsidian (natural volcanic glass, predominantly SiO₂)

Blue glassy cabochon, likely blue quartz or synthetic glass

Possibly dyed blue chalcedony/quartz (SiO₂); visual identification is inconclusive

Blue opalite glass (likely man-made)

Opalite glass; a silica-based amorphous glass, not natural opal

Goldstone (brown goldstone)

Man-made aventurine glass, typically copper-bearing silica glass

Blue cabochon gemstone, likely synthetic glass or dyed stone

Indeterminate from image; possible glass, synthetic spinel, sodalite, or lapis lazuli

Flint or chert fragment

Microcrystalline quartz (SiO₂), likely flint/chert

Possible tumbled obsidian

Volcanic glass, primarily rhyolitic silica glass (SiO₂-rich)

Red cabochon gemstone ring (likely glass or synthetic stone)

Undetermined; the image does not establish a natural mineral identity

Polished black stone, likely obsidian

Volcanic glass; primarily silica-rich, noncrystalline SiO₂

Polished opalite (likely man-made opalescent glass)

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

Goldstone (likely blue-free synthetic goldstone pendant)

Synthetic aventurine glass; silica glass with dispersed metallic copper crystals

Tumbled pale quartz/chalcedony fragment

Quartz (SiO₂), possibly microcrystalline chalcedony

Tumbled cat’s-eye stone, likely cat’s-eye glass or imitation

Undetermined; natural chrysoberyl cat’s-eye is BeAl₂O₄, but the photo does not establish that identity

Tumbled yellow-brown quartzite or jasper

Quartzite, predominantly microcrystalline quartz (SiO₂), possibly iron-stained jasper

Blue goldstone

Man-made aventurine glass containing metallic copper particles; not a natural mineral

Black onyx or black obsidian bead bracelet

Likely black chalcedony (microcrystalline quartz, SiO₂); possibly volcanic glass (obsidian, SiO₂)

Black obsidian (probable)

Volcanic glass; primarily SiO₂-rich rhyolitic composition

Sea Glass

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

Small colored gemstone or glass cabochons (uncertain)

Not identifiable from the image; the pieces may be colored glass or synthetic stones rather than natural minerals.

Polished black stone, likely basalt or dark river pebble

Basalt; chiefly plagioclase feldspar and pyroxene, commonly with minor magnetite

Tumbled black stone, likely black obsidian

Obsidian — natural volcanic glass, predominantly silica-rich rhyolitic composition

Dyed or synthetic turquoise-blue glass-like specimen

Likely man-made colored glass or resin; exact identification requires testing

Tumbled opalite (likely man-made glass)

Opalite glass; a synthetic opalescent glass, not a natural mineral species

Small gray translucent stone, possibly quartz or glassy mineral

Uncertain; likely microcrystalline quartz (SiO₂), but the image is insufficient for definitive identification

Obsidian (Blue)

Volcanic Glass (SiO2)

Tumbled mahogany obsidian

Volcanic glass, predominantly rhyolitic silica (SiO₂), with iron-oxide inclusions

Tumbled blue glass-like specimen, possibly dyed chalcedony or synthetic glass

Uncertain; possible dyed quartz/chalcedony (SiO₂), but appearance strongly suggests cobalt-blue glass

Goldstone (blue/black aventurine glass)

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

Black obsidian (possibly industrial glass or slag)

Volcanic glass; predominantly rhyolitic composition, chiefly SiO₂

Polished black stone, possibly basalt or black jasper

Basalt (fine-grained mafic rock) or microcrystalline quartz if jasper

Black polished stone, likely black obsidian

Obsidian; volcanic glass, predominantly silica-rich rhyolitic composition