Uncertain

Quartz-rich breccia or silicified rock with metallic sulfide mineralization

Microcrystalline and crystalline SiO₂, likely quartz/chalcedony, with possible pyrite or other sulfides

Likely quartz crystal

Quartz (SiO₂), possibly milky or iron-stained quartz

Dark river-worn stone, likely basalt

Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase, pyroxene, and commonly olivine

Iron-rich sandstone or weathered siltstone

Clastic siliciclastic sedimentary rock, likely ferruginous sandstone (mostly quartz and feldspar cemented by iron oxides)

Tumbled orange chalcedony or carnelian

Microcrystalline quartz (SiO₂), likely iron-bearing chalcedony

Green iridescent glass cabochon or synthetic gemstone

Likely synthetic glass; possibly coated synthetic quartz or lab-created green gemstone

Granite or granitic gneiss

Coarse quartz–feldspar–mica rock; possible gneissic variant

Rhyolite (possibly porphyritic and altered)

Volcanic felsic rock; primarily quartz, alkali feldspar, plagioclase, and volcanic glass, with iron-oxide alteration

Tumbled reddish-brown chalcedony, possibly carnelian

Chalcedony (microcrystalline quartz), SiO₂; red variety commonly called carnelian

Possible weathered chert or flint pebble

Microcrystalline quartz (SiO₂), possibly chalcedony-rich chert

Tumbled jasper (likely brecciated or orbicular jasper)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide inclusions

Possible weathered metallic mineral specimen

Uncertain; possibly native copper-bearing rock or iron sulfide in a gray host matrix

Tumbled amber-like chalcedony or resinous fossil material

Likely chalcedony (microcrystalline SiO₂), though the appearance could also indicate copal/amber

Tumbled black stone, likely black tourmaline or obsidian

Schörl tourmaline: NaFe3Al6(BO3)3Si6O18(OH)4, or volcanic glass (obsidian: mainly SiO2)

Unidentified fine mineral/rock powder

Indeterminate from image; possibly crushed quartz-rich sand or finely milled rock

Likely polished/tumbled dark mineral or glassy rock fragment

Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian

Rounded quartz-rich pebble

Likely quartzite or quartz-rich sandstone; primarily silicon dioxide (SiO₂)

Weathered porphyritic volcanic rock, likely andesite

Porphyritic andesite; primarily plagioclase feldspar, pyroxene, and possibly amphibole in a fine-grained groundmass

Tumbled honey-colored quartz pebble

Quartz, silicon dioxide (SiO₂)

Uncertain pale green-gray mineral/rock fragment

Possibly serpentine-bearing rock or greenstone; exact identification requires testing

Likely calcite crystal fragment

Calcite (CaCO₃)

Green translucent mineral pebble (possibly chrysoprase or green quartz)

Unconfirmed; possibilities include chalcedony (SiO₂) or quartz (SiO₂)

Likely vesicular volcanic rock (possibly pumice or scoria)

Vesicular volcanic rock; exact identification requires a fresh, close-up sample

Rounded granite cobble

Granite, a coarse-grained felsic intrusive igneous rock composed chiefly of quartz, feldspar, and mica

Turquoise-colored bead earrings

Likely dyed or stabilized turquoise; exact stone cannot be confirmed from the photo

Blue-green copper mineral rock, likely chrysocolla-bearing matrix

Chrysocolla (hydrated copper aluminosilicate), commonly with malachite, limonite, and quartz

Tiger’s-eye-rich breccia or jasper

Quartz-rich silicified rock, likely containing iron oxides (SiO₂ with Fe oxides/hydroxides)

Tumbled fluorite (likely)

Fluorite, calcium fluoride (CaF₂)

Metallic sulfide-bearing rock, possibly galena-rich ore

Likely galena (PbS) with iron sulfides and gangue; exact identification requires testing

Iron-rich breccia or hematite-bearing ironstone

Hematite–goethite ironstone, possibly brecciated jasper; chiefly Fe₂O₃ and FeO(OH)

Tumbled quartz (likely clear/milky quartz)

Quartz, silicon dioxide (SiO₂)

Iron-rich concretion (probable hematite/limonite nodule)

Goethite–hematite concretion; FeO(OH) and Fe₂O₃, possibly with quartz/clay

Beaded bracelet, likely green aventurine and yellow citrine or dyed quartz

Quartz, SiO₂ (green aventurine may contain fuchsite inclusions)

Quartz-rich geode or mineralized cavity in host rock

Likely a quartz-bearing geode; the pale crystals may be quartz (SiO₂), but the photo is not detailed enough for a firm identification.

Weathered limestone boulder

Limestone, composed mainly of calcite (CaCO₃); exact identification cannot be confirmed from the image alone.

Polished agate nodule

Agate, a banded variety of microcrystalline quartz (SiO₂)

Quartz with a pale pink crystal

Quartz, SiO₂; likely milky quartz with iron-stained or faintly pink quartz

Polished banded agate

Agate, a microcrystalline variety of quartz (SiO₂), often chalcedony

Red faceted gemstone, likely synthetic ruby

Corundum (Al₂O₃), chromium-colored; possibly flame-fusion synthetic ruby

Weathered quartzite pebble

Quartzite, composed predominantly of quartz (SiO₂)

Likely rough carnelian (orange-brown chalcedony)

Chalcedony, microcrystalline quartz (SiO₂); variety possibly carnelian

Tumbled carnelian

Chalcedony (microcrystalline quartz), SiO₂