Tektite (Natural Glass)

Probable amber fragment

Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)

Diamond

Diamond (pure carbon; C)

Quartz (River Pebble)

Quartz (SiO₂ - Silicon Dioxide)

Slag (Industrial Glassy Byproduct)

Ferro-silicate Slag

Chert / Flint

Chert (varieties include Flint)

Black Tourmaline

Schorl (Na(Fe2+)_{3}Al_{6} (BO_{3})_{3} (Si_{6}O_{18})(OH)_{4})

Quartz (likely Jasper or Chert variety)

Quartz (SiO₂)

Pink Stained Rock (Likely Quartzite or Sandstone with Iron Oxide Staining)

Quartzite (metamorphic) or Sandstone (sedimentary); coloration likely due to hematite or other iron oxides.

Black Tourmaline (Schorl)

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Peridot and Citrine Gemstones (in a ring setting)

Peridot (Olivine: (Mg,Fe)2SiO4), Citrine (Quartz: SiO2)

Rhodonite beads (possibly dyed or treated, or lower quality Rhodonite)

Manganese inosilicate, (Mn,Fe,Mg,Ca)SiO3

Green Aventurine

Aventurine Quartz (SiO2 with fuchsite inclusions)

Sandstone

Sandstone (lithified arenite/wacke)

Peridot (likely, given the color and bead form)

Olivine, variety Peridot (Mg,Fe)2SiO4

Sandstone (Pebble/Conglomerate fragment)

Sandstone (clastic sedimentary rock)

Sandstone

Sandstone (Clastic Sedimentary Rock)

Aventurine

Aventurine Quartz (SiO2 with inclusions)

Quartz

Quartz (SiO2 - Silicon Dioxide)

Amethyst

Quartz variety; chemical formula: SiO₂ (silicon dioxide) with Fe³⁺ impurities

Weathered granite or granitic pegmatite cobble

Granite/granitic rock, composed mainly of quartz (SiO₂), feldspar, and minor biotite or other dark minerals; the reddish-brown areas may be iron-oxide staining or weathered accessory minerals

Amber (Black)

Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)

Smoky Quartz

SiO2 (Silicon Dioxide)

Tumbled carnelian agate with dark mineral inclusions

Carnelian, an orange variety of microcrystalline quartz (chalcedony), SiO₂; dark inclusions are likely iron oxides/hydroxides, possibly hematite, goethite, or a basaltic/matrix fragment

Agate

Agate (a cryptocrystalline variety of Quartz, SiO₂)

Black Tourmaline (Schorl)

Schorl (Na(Fe^2+)3Al6(Si6O18)(BO3)3)(OH)3(OH))

Aquamarine and clear quartz

Aquamarine (Be3Al2Si6O18), Quartz (SiO2)

Green Agate

Silicon dioxide (SiO₂)

Quartz (Rock Crystal) with minor impurities

Quartz (SiO2)

Smoky Quartz

Smoky Quartz (SiO2)

Sandstone (likely a river or beach pebble)

Sandstone (a clastic sedimentary rock)

Banded agate pendant (likely carnelian or brown-and-white chalcedony agate)

Agate, a banded variety of chalcedony; microcrystalline quartz, SiO₂, with iron-oxide coloration

Clear Quartz (beads in a bracelet)

Quartz (SiO2)

Agate (or Banded Agate)

Agate (a variety of Chalcedony, which is a cryptocrystalline form of Quartz); Chemical Formula: SiO₂ (Silicon Dioxide)

Agate

Agate (a variety of Chalcedony, SiO2)

Flint

Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)

Polymictic breccia, possibly volcanic breccia

Polymictic clastic breccia; likely a matrix-supported breccia containing lithic fragments, quartz, feldspar, and dark mafic minerals

Hematite

Hematite (Fe2O3)

Banded Chert or Chert with Quartz Veins

Chert (SiO2)

Quartz (variety of colors)

SiO2 (Silicon Dioxide)

Cobalt Glass Slug (Man-made Glass)

Amorphous Silica with Cobalt Oxide (SiO2 + CoO)

Sea Glass

Silicon dioxide (mostly)

Sea Glass

Man-made vitreous material (silica-based glass)