Uncertain

Iron-stained chert (possible jasper)

Microcrystalline quartz (SiO₂), likely iron-oxide stained

Vesicular volcanic rock, likely scoria

Scoria; typically basaltic to andesitic composition, chiefly plagioclase, pyroxene, and volcanic glass

Agatized fossil fragment, possibly silicified coral

Chalcedony (microcrystalline SiO₂) replacing carbonate fossil material

Polished copper-bearing mineral specimen, likely malachite-rich copper ore

Malachite, Cu₂CO₃(OH)₂, possibly mixed with chrysocolla or limonite

Polished yellow-green serpentine pendant

Serpentine-group minerals, chiefly antigorite and/or lizardite; approximate formula Mg3Si2O5(OH)4

Polished ocean jasper (orbicular jasper), probable

Microcrystalline quartz (SiO₂), chiefly chalcedony with iron-oxide and other mineral inclusions

Red cabochon gemstone, likely carnelian

Carnelian: orange-red chalcedony, microcrystalline quartz (SiO₂)

Tumbled translucent quartz or chalcedony fragment

Silicon dioxide, SiO₂; likely quartz/chalcedony

Raw mica-bearing metamorphic rock, likely schist

Mica schist; chiefly muscovite/biotite mica with quartz and feldspar

Inlaid stone ring (likely jasper or agate)

Likely microcrystalline quartz (chalcedony, SiO₂), possibly jasper, with decorative mineral inlays

Likely raw blue kyanite specimens

Kyanite, Al₂SiO₅

Tumbled serpentine (likely)

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

Polished mahogany obsidian (likely) pendant

Obsidian, natural volcanic glass; compositionally rhyolitic, chiefly silica-rich glass

Tumbled green aventurine (probable)

Aventurine quartz, SiO₂ with fuchsite mica inclusions

Quartz–pyrite druzy slab

Quartz (SiO₂) with pyrite (FeS₂), likely in a geode or hydrothermal vein

Likely serpentinite or serpentinized ultramafic rock

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and relict olivine/pyroxene

Likely basalt (possibly vesicular basalt)

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine, with iron-titanium oxides

Polished jasper pebble

Microcrystalline quartz (SiO₂), commonly iron-stained jasper/chert

Fossiliferous limestone with a shell fossil

Calcite-rich limestone (primarily CaCO₃), containing a likely fossil shell

Tumbled agate (likely chalcedony)

Microcrystalline quartz, SiO₂; agate is banded chalcedony, though banding is not clear in this specimen

Likely lateritic ironstone (limonite/goethite-rich)

Goethite, α-FeO(OH), with possible limonite and clay impurities

Weathered iron-rich rock, likely hematite-bearing sandstone or ironstone

Hematite/goethite-bearing ferruginous sandstone or ironstone; exact identification requires testing

Tumbled black stone, likely black obsidian

Obsidian — natural volcanic glass, primarily SiO₂

Milky quartz with iron staining

Quartz (SiO₂), possibly with minor iron-oxide inclusions

Likely quartz-rich granitic rock

Granite or granitic pegmatite; mainly quartz (SiO₂) with feldspar and minor mica

Serpentinite (likely serpentinized ultramafic rock)

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), with possible magnetite, olivine, pyroxene, and talc

Raw purple fluorite crystal (tentative)

Fluorite, calcium fluoride (CaF₂)

Metallic sulfide ore, likely pyrite-bearing rock

Pyrite (FeS₂), possibly with marcasite or other sulfides

Weathered amphibolite or mafic metamorphic rock

Amphibolite; chiefly hornblende amphibole and plagioclase feldspar

Sulfur crystals on iron-rich matrix

Native sulfur (S₈), likely with iron oxides/hydroxides such as limonite

Tiger’s-eye rough

Quartz (SiO₂) with fibrous crocidolite-derived inclusions

Sulfur (native sulfur)

Native sulfur, S₈

Turquoise cabochon or turquoise-bearing material

Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O

Pyrite-bearing sulfide ore

Pyrite (FeS₂), possibly mixed with chalcopyrite and/or other sulfides

Fossiliferous limestone, likely coralline or stromatolitic

Biogenic limestone; predominantly calcite (CaCO₃)

Polished turquoise (likely stabilized)

Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

Native gold-bearing quartz/rock specimen

Native gold (Au) in quartz and iron-oxide matrix

Biotite gneiss (probable)

Foliated gneiss composed mainly of quartz, feldspar, and biotite mica

Rose quartz (likely)

Quartz, silicon dioxide (SiO₂), pink variety

Biotite-rich schist (mica schist)

Mica schist, chiefly quartz + biotite mica; approximate formula for biotite K(Mg,Fe)3AlSi3O10(F,OH)2

Tumbled mahogany obsidian (likely)

Volcanic glass, predominantly silica-rich rhyolitic glass; exact variety uncertain from image

Likely iron-stained quartz or quartzite

Quartz (SiO₂), possibly quartzite; yellow-brown coloring likely from iron oxides