Uncertain

Polished ocean jasper (orbicular jasper)

Silicified rhyolite, composed mainly of microcrystalline quartz (SiO₂)

Black tourmaline (schorl)

Schorl, a sodium–iron borosilicate: NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Flint (chert)

Microcrystalline quartz (SiO₂), commonly called chert or flint

Polished picture jasper (likely)

Silica-rich microcrystalline quartz, SiO₂, with iron-oxide and other mineral inclusions

Likely iron-stained quartz

Quartz (SiO₂), with possible iron-oxide staining; identification from the photo is provisional

Likely rough quartz crystal fragment

Quartz, SiO₂

Orange agate (chalcedony), possibly a small tumbled or naturally water-worn piece

Chalcedony, microcrystalline SiO₂; agate is banded chalcedony

Orange quartzite pebble

Quartzite, composed predominantly of quartz (SiO₂), with iron-oxide staining

Tumbled banded agate

Microcrystalline quartz (SiO₂), a variety of chalcedony

Likely rough blue-gray kyanite

Kyanite, Al₂SiO₅

Porphyritic volcanic rock (likely porphyritic andesite)

Porphyritic andesite; chiefly plagioclase feldspar with fine-grained volcanic groundmass

Quartz-bearing pegmatite

Quartz (SiO₂) with feldspar and mica, likely a granitic pegmatite

Blue glass-like heart pendant, likely synthetic blue spinel or colored glass

Unconfirmed; possibly synthetic spinel (MgAl₂O₄) or cobalt-colored glass

Black obsidian

Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)

Light-colored carbonate pebble, likely limestone

Limestone; predominantly calcite (CaCO₃), possibly micritic or fossiliferous

Yellow-green tumbled stone, possibly serpentine

Serpentine-group minerals, commonly antigorite or lizardite; composition approximately Mg₃Si₂O₅(OH)₄

Milky quartz (likely iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

Tumbled river pebble, likely limestone or weathered chert

Indeterminate carbonate/siliceous pebble; possible micritic limestone or chert

Foliated metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss (provisional identification)

Tumbled jasper/quartz-rich pebble

Microcrystalline quartz (SiO₂), likely jasper with iron-oxide inclusions

Blue-gray flint or chert fragment

Microcrystalline quartz (SiO₂), likely flint/chert

Quartz-rich granite or granitic pegmatite fragment

Granite; predominantly quartz (SiO₂), feldspar, and minor mica/iron oxides

Polished dark speckled stone, likely granite or diorite

Granite–diorite granitoid; chiefly quartz, feldspar, and dark mafic minerals

Rounded quartz-rich pebble, likely quartzite or vein quartz

Quartzite (mostly SiO₂), possibly quartz-rich metamorphic rock

Tumbled milky quartz (probable)

Quartz, silicon dioxide (SiO₂)

Porphyritic volcanic rock, likely andesite or rhyolite

Porphyritic andesite–rhyolite; chiefly plagioclase, quartz, and altered ferromagnesian minerals in a fine groundmass

Small metallic meteorite fragment (probable stony-iron or iron meteorite)

Unclassified meteoritic material; exact classification requires chemical and petrographic testing

Weathered quartz-rich metamorphic rock (likely gneiss or quartzite)

Quartz (SiO₂) with probable feldspar, mica, and iron-oxide alteration

Weathered quartz-bearing sandstone or quartzite

Quartzite (SiO₂-rich), possibly weakly metamorphosed sandstone

Serpentinite with green serpentine inclusion

Serpentinite; serpentine-group minerals, chiefly antigorite, lizardite, or chrysotile, with possible magnetite

Iron-oxide-rich rock fragment (likely limonite/goethite)

Goethite, α-FeO(OH), possibly mixed with limonite and other iron oxides

Turquoise beads (likely dyed howlite or magnesite imitation)

Turquoise: CuAl₆(PO₄)₄(OH)₈·4H₂O; the pictured beads may instead be dyed Ca-Mg carbonate, which cannot be confirmed visually

Banded agate (likely moss or plume agate)

Microcrystalline quartz (SiO₂), chiefly chalcedony

Polished yellow-brown agate (likely carnelian or chalcedony)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide coloration

Tumbled carnelian agate

Microcrystalline quartz (SiO₂), chiefly chalcedony with iron-oxide coloration

Black tourmaline (schorl)

Schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Quartz-rich metamorphic rock, likely quartzite

Quartzite (mostly microcrystalline quartz, SiO₂)

Likely rose quartz fragment

Quartz, silicon dioxide (SiO₂), pink variety

Rough green calcite

Calcite, CaCO₃

Tiger’s-eye (likely cabochon gemstone)

Quartz variety, chiefly SiO₂, with fibrous crocidolite-derived inclusions

Tumbled orange aventurine (likely quartzite)

Quartz-rich rock, primarily microcrystalline quartz (SiO₂)

Polished peach moonstone

Moonstone, a feldspar variety; likely orthoclase (KAlSi₃O₈)