Tektite (Natural Glass)

Quartz crystal point (likely smoky or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

Pink feldspar fragment (probable orthoclase or microcline)

Potassium feldspar, KAlSi₃O₈

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Pink Granite

Phaneritic Felsic Igneous Rock

Pink chalcedony (likely rough agate/chalcedony)

Microcrystalline quartz, SiO₂; chalcedony variety, possibly iron-bearing

Banded Agate (River Stone)

Agate (Silicon Dioxide - SiO2)

Mixed polished river pebbles, predominantly quartzite and quartz

Quartzite (SiO₂), quartz (SiO₂), with possible feldspar-rich and iron-stained lithologies

Basalt (Water-worn Pebble)

Basalt (Mafic Extrusive Igneous Rock)

Flint or chert flake

Microcrystalline quartz (SiO₂), commonly chalcedony with possible impurities

Small purple quartz crystal, likely amethyst

Amethyst: violet variety of quartz, silicon dioxide (SiO₂)

Halite

Sodium Chloride (NaCl)

Rounded pink granite pebble

Granite, chiefly quartz, alkali feldspar, plagioclase, and minor biotite/hornblende

Quartz geode

Quartz (SiO₂), likely drusy/microcrystalline quartz lining a geode cavity

Polished chert or jasper cobble

Microcrystalline quartz (SiO₂), commonly called chert; iron-oxide-bearing varieties are jasper

Amethyst cluster

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron-related defects

Greenish translucent mineral fragment

Indeterminate; possibly serpentine, epidote, or green glassy feldspar

Granite

Phaneritic Intrusive Igneous Rock (composed of Quartz, Feldspar, and Mica)

Red jasper / iron-rich chert

Microcrystalline quartz (SiO₂) colored by hematite/goethite

Polished brecciated jasper

Jasper (microcrystalline quartz, SiO₂), likely iron-oxide-rich breccia

Quartzite (Beach Pebble)

Quartzite (primarily SiO2)

Amygdaloidal Rhyolite

Rhyolite (felsic volcanic rock) with amygdules

Jasper (Iron-stained Chalcedony)

SiO2 with Fe2O3 (Iron Oxide) impurities

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Jasper (specifically Polychrome or Desert Jasper)

Silicon Dioxide (SiO2) with impurities

Sandstone (Quartzose Sandstone)

Clastic sedimentary rock (SiO2 primary composition)

Rutilated quartz crystal

Quartz, silicon dioxide (SiO₂), containing rutile inclusions (TiO₂)

Porphyritic granite or granitic gneiss

Quartz–feldspar–mica granitoid; exact identification requires testing

Polished orbicular jasper

Orbicular jasper; microcrystalline quartz (SiO₂) with iron oxides and altered volcanic minerals

Chert

Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)

Black-and-white jasper

Jasper, microcrystalline quartz (SiO₂), with contrasting white mineral inclusions

Yellow Agate

Chalcedony (cryptocrystalline Quartz), SiO2

Granite pebble

Coarse-grained felsic intrusive igneous rock; mainly quartz, alkali feldspar, plagioclase, and minor biotite or amphibole

Tumbled jade-like stone, likely nephrite jade

Nephrite: fine-grained interlocking tremolite–actinolite, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂

Tumbled carnelian agate

Cryptocrystalline quartz (SiO₂), chalcedony variety with iron-oxide coloration

Chert / Flint (Brecciated or Fossiliferous Limestone with Silicification)

Sedimentary cryptocrystalline quartz (SiO2)

Green Jasper

Silicon Dioxide (SiO2) with iron silicate inclusions

Yellow Chalcedony (Agate/Carnelian variant)

Silicon Dioxide (SiO₂)

Yellow Quartz (Citrine Quartz Pebble)

Silicon Dioxide (SiO2)

Petrified wood

Silicified fossil wood; commonly quartz (SiO₂) replacing wood

Raw quartz crystal

Quartz (silicon dioxide, SiO₂)

Selenite (gypsum crystal)

Gypsum, calcium sulfate dihydrate (CaSO₄·2H₂O), likely the variety selenite

Pumice (likely)

Pumice (extrusive igneous rock)