Tektite (Natural Glass)

Rough Green Sapphire (Corundum)

Corundum (Al2O3 - Aluminum Oxide with trace elements)

Obsidian arrowhead

Volcanic glass (predominantly rhyolitic SiO₂)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon dioxide (SiO₂)

Massive Quartz (Yellow/Citrine variety)

Silicon Dioxide (SiO2)

Blue Topaz (facetted in jewelry)

Aluminum silicate fluoride hydroxide (Al2SiO4(F,OH)2)

Amethyst

Amethyst (variety of Quartz, SiO2)

Tumbled brown stone, likely tiger’s-eye or jasper

Quartz-rich microcrystalline silica, likely SiO₂ (possible tiger’s-eye; identification uncertain from image)

Quartz (Citrine/Milky variety)

Silicon Dioxide (SiO2)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Amethyst (Chevron or Banded Amethyst)

Silicon Dioxide (SiO2 with iron impurities)

Amethyst

Amethyst (Silicon Dioxide, SiO2 with Iron impurities)

Rounded river or beach pebble

Likely quartz-rich sandstone or quartzite; exact identification requires a close-grained view and hardness test

Pink Granite

Phaneritic Igneous Rock (high K-Feldspar content)

Quartzite

Quartzite (primarily SiO2)

Smoky Quartz and Clear Quartz Geode

Silicon Dioxide (SiO2)

Rose Quartz

Silicon Dioxide (SiO2)

Polished yellow jasper or opaque chalcedony bead

Microcrystalline quartz (SiO₂), likely iron-oxide-stained jasper

Rounded flint or chert pebble

Microcrystalline quartz (SiO₂), commonly chalcedony with possible impurities

Smoky Quartz (Tumbled)

Smoky Quartz (SiO2 - Silicon Dioxide)

Citrine

Silicon Dioxide (SiO2) - Yellow Quartz variety

Smoky Quartz

Silicon Dioxide (SiO2)

Smoky Quartz

Smoky Quartz (SiO2: Silicon Dioxide)

Tumbled purple agate (likely grape agate or amethystine chalcedony)

Microcrystalline quartz, SiO₂; purple coloration commonly from iron, manganese, or inclusions

Red Jasper

Silicon Dioxide with iron impurities (Quartz variety, SiO2)

Ruby (Corundum)

Aluminum oxide (Al2O3) with Chromium traces

Yellow chalcedony (likely citrine or iron-stained quartz)

Microcrystalline quartz, SiO₂; yellow coloration likely from iron oxides or included quartz varieties

Chert (Green Jasper)

Microcrystalline Quartz (SiO2) with iron silicate inclusions

Chert (Flint variety)

Chert (Cryptocrystalline Quartz, SiO2)

Citrine Quartz Cluster

Silicon Dioxide (SiO2)

Rock crystal quartz fragment

Quartz (silicon dioxide, SiO₂)

Amethyst

Silicon Dioxide (SiO2) with trace Iron impurities

Colorless faceted gemstone, likely cubic zirconia

Cubic zirconia (zirconium dioxide, ZrO₂); visual confirmation is unavailable

Yellow Quartz (Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Polished agate slice

Agate, a banded variety of chalcedony (microcrystalline SiO₂)

Amethyst quartz cluster

Quartz, silicon dioxide (SiO₂), purple variety amethyst

Sandstone (Quartz Sandstone)

Arenite (primarily SiO2)

Mixed tumbled stone collection

Assorted minerals, likely including quartz, jasper, agate, and possibly obsidian or hematite

Jasper or Agate-bearing Chert

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Rounded brown-gray stone, possibly weathered conglomerate or sandstone

Indeterminate clastic sedimentary rock; likely poorly cemented sandstone/conglomerate

Pink Granite

Granite (composed of Potassium Feldspar, Quartz, and Plagioclase)

Ferrosilicon Slag (Industrial Vitrified Glass)

Vitreous Silicate Residue