Mineral Like (Natural Glass)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Tumbled green aventurine quartz

Aventurine quartz — microcrystalline quartz (SiO₂) with fuchsite or other mica inclusions

Tumbled green aventurine (likely)

Quartz variety, SiO₂, containing fuchsite or other green inclusions

Polished orange agate/jasper cabochon

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide coloration; exact variety uncertain

Orange Quartz (Citrine Quartz variety)

Silicon Dioxide (SiO2)

Amethyst

Amethyst (Silicon Dioxide with iron impurities, SiO2)

Amethyst

SiO2 (Silicon Dioxide) - Purple variety of Crystalline Quartz

Polished agate or chalcedony pebble

Microcrystalline quartz (SiO₂), likely chalcedony/agate

Polished tiger iron

Tiger iron, a banded aggregate of tiger’s-eye (quartz), red jasper, and hematite/magnetite

Sandstone

Clastic Sedimentary Rock

Sandstone (Sedimentary Rock)

Arenite (SiO2 based)

Tumbled rose quartz

Quartz, silicon dioxide (SiO₂), pink variety

Quartz-rich rock with a purple amethyst-like cavity

Likely quartz vein or amethyst-bearing geode; purple area may be quartz (SiO₂) colored by trace iron

Amethyst (Agate/Chalcedony variety)

Silicon Dioxide (SiO2) with iron impurities

Chert

Microcrystalline Quartz (SiO2)

Small translucent tumbled crystal or gemstone

Indeterminate; likely quartz (SiO₂), possibly citrine or glass-like chalcedony

Amethyst cluster

Amethyst, purple quartz (SiO₂)

Amethyst crystal point

Amethyst, purple quartz (SiO₂)

Sandstone

Arenite

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Diamond (or Cubic Zirconia)

Carbon (C) / Cubic Zirconium Dioxide (ZrO2)

Diamond

Natural Carbon (C)

Quartz with Iron Oxide Staining (Citrine-like Quartz)

Silicon Dioxide (SiO2)

Goldstone

Avventurina (Man-made Glass with Copper inclusions)

Sandstone (Stream-rounded)

Arenite (SiO2 based)

Sandstone (Quartzose Sandstone)

Arenite (primarily SiO2)

Tumbled white-gray stone, likely calcite or marble

Calcite (CaCO₃), possibly fine-grained marble (recrystallized calcite)

Faceted gemstones, likely assorted quartz or glass-like gems

Not determinable from the photograph; possible quartz (SiO₂), topaz, or synthetic cubic zirconia

Smoky Quartz

Silicon Dioxide (SiO2)

Smoky Quartz and Clear Quartz Geode

Silicon Dioxide (SiO2)

Orange chalcedony (carnelian-like), possibly iron-stained quartz

Microcrystalline quartz, SiO₂ (chalcedony); orange coloration likely from iron oxides/hydroxides

Green Quartz (including Prase or Aventurine variants)

Silicon Dioxide (SiO2) with inclusions (likely Actinolite or Chlorite)

Tumbled green aventurine (probable)

Quartz variety; SiO₂ with disseminated fuchsite or other mica inclusions

Blue quartzite or blue aventurine glass-like aggregate

Quartzite, predominantly SiO₂ (identification uncertain from image)

Slag Glass (Leland Blue variant)

Anthropogenic Vitreous Silicate

Rainbow Hematite (Titanium-Coated Hematite)

Titanium-treated Hematite (Fe2O3)

Sandstone (with Iron Staining)

Clastic sedimentary rock (SiO2 with Fe2O3 impurities)

Polished agate or chalcedony slice (uncertain)

Microcrystalline quartz, SiO₂; possibly fossil-bearing chalcedony

Milky Quartz

Crystalline Silicon Dioxide (SiO2)

Green Aventurine

Silicon Dioxide (SiO2) with Fuchsite inclusions

Diamond

Carbon (C)