Antropogenic (Man Made Glass Byproduct)

Chert (Flint)

Silicon dioxide (SiO2)

Green obsidian (likely moldavite)

Natural volcanic glass; if extraterrestrial-impact glass, moldavite (tektite)

Tumbled green glassy mineral, possibly aventurine or fluorite

Uncertain; likely quartz variety (aventurine quartz, SiO₂) or green fluorite (CaF₂)

Chert

Chert (Microcrystalline Quartz)

Likely chert (flint) fragment

Microcrystalline quartz, SiO₂

Colorless faceted gemstone, likely quartz

Quartz (SiO₂), tentative identification; the photo is insufficient to confirm the material

Terrazzo (Synthetic Composite Rock)

Cementitious or Epoxy Resin-bound Aggregates

Mixed polished gemstone and mineral collection

Primarily quartz varieties (SiO₂), plus probable aventurine, rose quartz, amethyst, agate, jasper, serpentine, feldspar, and possibly dyed or man-made glass pieces

Flint (gray chert)

Microcrystalline quartz (SiO₂), a variety of chert

Pearl and Garnet Glass

Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass

Flint (chert) fragment

Microcrystalline quartz (SiO₂), commonly called flint when dark

Red cabochon gemstone ring

The stone may be carnelian (orange-red chalcedony, SiO₂); the image is insufficient to identify it reliably.

Weathered chert or chalcedony nodule

Microcrystalline quartz (SiO₂), possibly silicified limestone or agate-like chalcedony

Sea Glass (Frosted Glass)

Amorphous Silica (SiO2) with various additives

Pumice

Pumice (Vesicular volcanic glass)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Black tumbled stone, possibly obsidian

Obsidian (natural volcanic glass; composition varies, typically silica-rich)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (specifically Jasper or Flint)

Cryptocrystalline Quartz (SiO2)

Chert (Flint/Jasper variety)

Microcrystalline Quartz (SiO2)

Polished, carved gemstone (possibly dyed agate or glass-like material)

Unconfirmed from the image; no specific mineral can be identified reliably

Polished blue chalcedony (possibly agate)

Microcrystalline quartz, SiO₂; chalcedony, potentially banded agate

Faceted clear gemstone ring, likely quartz or glass imitation

Unidentified colorless faceted material; quartz (SiO₂) is possible, but the image cannot distinguish it from glass or another gem

Blue Goldstone

Aventurine Glass (Silicon Dioxide with metal inclusions)

Blue glass-like tumbled specimen

Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image

Diamond (or Diamond Simulant)

Carbon (C) or Cubic Zirconia (ZrO2)

Faceted Glass (Costume Jewelry)

Amorphous Silicon Dioxide with colorants (Glass)

Malaysian 50 Sen Coin

Coinage (specific alloy unknown without metallurgical analysis, but typically brass or bronze for this denomination and era)

Pumice

Pumice (Vitreous volcanic rock)

Tumbled chert or jasper pebble

Microcrystalline quartz (SiO₂), likely chert/jasper

Chert (Flint)

Silicon Dioxide (SiO2)

Artificial Rock Face (Faux Rock)

Glass Fiber Reinforced Concrete (GFRC)

Rounded gray pebble, likely quartzite

Quartzite (predominantly crystalline quartz, SiO₂); identification is tentative from the image

Pumice or vesicular volcanic tuff

Pumice: highly vesicular volcanic glass, chiefly rhyolitic to dacitic; possible tuff: lithified ash and pumice fragments

Chert Nodule

Microcrystalline Quartz (SiO2)

Chert (specifically Flint)

Chert (SiO2)

Pink Granite

Phaneritic Felsic Igneous Rock (Granite)

Chert

Silicon dioxide (SiO2)

Tumbled blue chalcedony (possibly blue agate)

Microcrystalline quartz, SiO₂; chalcedony variety

Chert

Microcrystalline Quartz (SiO2)

Chipped Glass/Plastic Fragment

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

Aventurine

Aventurine Quartz (SiO2 with inclusions of Fuchsite)