Mineraloid (Human Made Geological Specimen)

Red Granite

Phaneritic Felsic Igneous Rock

Moss Agate

Silicon Dioxide (Chalcedony variety)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with minor feldspar, mica, and iron-oxide staining

Clear Quartz

Silicon Dioxide (SiO2)

Pyrite

Iron Pyrite (FeS2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Sandstone (Ferruginous/Red Sandstone)

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Rounded sandstone pebble

Quartz-rich sandstone (likely arkosic or lithic sandstone)

Tumbled yellow quartz (likely citrine or iron-stained quartz)

Quartz, silicon dioxide (SiO₂); yellow coloration likely from iron impurities

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Mixed Tumbled Rocks and Minerals Collection

Mixed Minerals and Rocks (Quartz, Feldspar, Jasper, Agate, Lapis Lazuli, Sodalite, Rose Quartz, Fluorite, etc.)

Weathered sandstone cobble

Quartz-rich sandstone, primarily SiO₂ with clay/iron-oxide cement

Quartz Pebble (Geode-like)

Silicon Dioxide (SiO2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Milky quartz (rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

Amber (Copal)

Organic gemstone, fossilized tree resin (often immature amber or copal)

Quartz crystal cluster

Quartz (silicon dioxide, SiO₂)

Quartz (Water-worn pebble)

Silicon Dioxide (SiO2)

Quartz Pebble (Milky Quartz)

Silicon Dioxide (SiO2)

Sandstone (Quartzose Sandstone)

Clastic Sedimentary Rock (Lithic arenite / Quartz arenite)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Likely weathered quartz-rich rock, possibly smoky quartz or chert

Quartz (SiO₂), though exact identification is uncertain from the photograph

Iron-Stained Quartz/Quartzite

Silicon Dioxide (SiO2) with iron oxides (Limonite/Hematite)

Possibly tumbled dark stone or mineral specimen

Indeterminate from image; possibly black tourmaline, basalt, or another dark silicate

Iron-stained quartz-rich rock, likely quartzite or silicified breccia

Quartz (SiO₂), possibly quartzite with limonite/goethite iron oxides

Clear Quartz

Silicon Dioxide (SiO2)

Blue Calcite

Calcium Carbonate (CaCO3)

Pyrite in Matrix (likely Quartz or Coal)

Iron Sulfide (FeS2)

Pyrite

Iron Disulfide (FeS2)

White Jade (Nephrite)

Nephrite, Ca2(Mg,Fe)5Si8O22(OH)2

Yellow Chalcedony

Chalcedony (a cryptocrystalline variety of Quartz, SiO₂)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Red Sandstone

Arenite (Iron-rich)

Chert / Flint

Silicon Dioxide (SiO2)

Tumbled chalcedony or carnelian

Microcrystalline quartz (SiO₂), likely iron-bearing chalcedony

Milky quartz

Quartz (silicon dioxide, SiO₂)

Sandstone Concretion

Clastic Sedimentary Concretion (SiO2 with Iron Oxide)

Labradorite (Polished Crystal Point)

Labradorite (a calcium-enriched feldspar mineral), (Ca, Na)(Al, Si)4O8

Petrified Wood

Silicon Dioxide (SiO2) permineralized organic matter

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)