Uncertain

Iron-rich weathered rock, possibly limonite/goethite-bearing breccia

Limonite (FeO(OH)·nH₂O), goethite (α-FeO(OH)), and iron oxides; host uncertain

Blue-green copper mineral specimen, likely chrysocolla or turquoise

Probable chrysocolla, hydrated copper phyllosilicate (Cu₂H₂Si₂O₅(OH)₄·nH₂O); turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O, is an alternative

Vesicular volcanic rock, likely scoria

Scoria; predominantly basaltic composition (plagioclase, pyroxene, olivine, and volcanic glass)

Fluorescent glassy mineral specimen, possibly hyalite opal

Hyalite (hydrated amorphous silica, SiO₂·nH₂O), tentative

Blue calcite (likely)

Calcite, CaCO₃

Milky quartz pebble

Quartz (SiO₂)

Iron-stained quartz-rich rock, possibly quartz vein material

Quartz (SiO₂) with iron-oxide staining; host rock not identifiable from the image

Polished golden-brown banded stone, likely tiger’s eye

Tiger’s eye (quartz with fibrous crocidolite pseudomorphs; SiO₂)

Polished chalcedony (likely moss or dendritic agate)

Microcrystalline quartz, SiO₂; chalcedony with possible iron-oxide and/or manganese dendrites

Iron meteorite (probable, possibly industrial iron slag)

Fe–Ni metallic alloy, commonly kamacite and taenite

Weathered granite fragment

Granite; primarily quartz, alkali feldspar, plagioclase, and minor biotite/hornblende

Pink granite (probable)

Granite, composed mainly of quartz, alkali feldspar, and plagioclase with minor mica

Blue cabochon ring stone, likely sapphire or synthetic blue corundum

Corundum (Al₂O₃), possibly chromium/iron-titanium-bearing sapphire

Rhyolite or fine-grained volcanic rock

Rhyolite ( felsic volcanic rock; commonly quartz + alkali feldspar)

Dark mafic metamorphic rock, likely amphibolite

Amphibolite; chiefly hornblende amphibole and plagioclase feldspar

Tumbled black stone, likely obsidian

Obsidian (natural volcanic glass; mainly silica-rich rhyolitic composition)

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and biotite/hornblende

Rose quartz (probable)

Quartz, SiO₂; pink coloration typically from trace inclusions or irradiation-related defects

Milky quartz-bearing rock, possibly quartzite or quartz vein

Quartz (SiO₂), likely with feldspar and minor iron-oxide inclusions

Likely raw garnet-bearing metamorphic rock

Garnet schist or garnet amphibolite; probable almandine garnet (Fe₃Al₂Si₃O₁₂)

Weathered vesicular limestone or calcareous tuff

Porous calcite-rich carbonate rock; composition likely predominantly CaCO₃ (calcite), with iron-oxide staining and possible silica/clay impurities

Possible tektite or volcanic glass specimen

Natural silica glass; composition commonly near SiO₂, but exact identification requires chemical testing

Red jasper / iron-rich chert

Microcrystalline quartz (SiO₂) colored by hematite/goethite

Weathered, iron-stained quartz-rich rock (likely quartzite)

Quartzite, composed mainly of quartz (SiO₂); identification is provisional from the photograph

Chert (flint)

Microcrystalline quartz, SiO₂ (chalcedony/quartz)

Aquamarine with feldspar and black tourmaline

Beryl (Be₃Al₂Si₆O₁₈), likely with feldspar and schorl (black tourmaline)

Red jasper pebble (likely)

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored by iron oxides

Biotite mica

Biotite, a potassium–iron–magnesium phyllosilicate mica; approximate formula K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂

Raw yellow quartz crystal, likely citrine

Quartz (SiO₂), iron-colored variety commonly sold as citrine

Yellow jasper or iron-stained chert

Microcrystalline quartz (SiO₂), commonly colored by goethite/limonite and other iron oxides

Botryoidal chalcedony (likely druzy quartz)

Microcrystalline quartz, SiO₂; chalcedony with a druzy quartz coating

Metallic sulfide-bearing pebble, likely pyrite in quartz or host rock

Probable pyrite (FeS₂), possibly with chalcopyrite (CuFeS₂) in a quartz-rich matrix

Polished serpentine (likely greenstone)

Serpentine-group minerals, chiefly antigorite/lizardite: Mg₃Si₂O₅(OH)₄

Tumbled golden-brown crystal, possibly citrine or quartz

Quartz (SiO₂), tentatively iron-stained or heat-treated citrine

Quartz-rich hydrothermal specimen, likely milky quartz with calcite

Quartz (SiO₂), with probable calcite (CaCO₃) and iron-oxide staining

Possible chalcopyrite-bearing sulfide fragment

Likely chalcopyrite (CuFeS₂), possibly with pyrite or bornite

Porphyritic basalt with quartz or feldspar phenocrysts

Basaltic rock; likely vesicular/porphyritic basalt, with pale mineral inclusions possibly quartz, feldspar, or calcite

Weathered granite-like rock fragments

Granite or granodiorite; chiefly quartz, feldspar, and biotite/hornblende

Blue calcite (likely)

Calcite, calcium carbonate (CaCO₃)

Azurite with malachite

Azurite, Cu₃(CO₃)₂(OH)₂, with possible malachite, Cu₂CO₃(OH)₂

Polished fossil coral pendant

Agatized or silicified colonial coral; commonly sold as fossil coral jasper

Polished brown calcite (likely honey calcite)

Calcite, calcium carbonate (CaCO₃)