Mineral (Processed Alloy)

Tumbled quartz (likely rose or milky quartz)

Quartz, silicon dioxide (SiO₂)

Cupronickel Coin

Copper-Nickel Alloy (typically 75% Cu, 25% Ni)

Green aventurine bead bracelet

Quartz (SiO₂), commonly green quartzite/aventurine colored by fuchsite mica or other inclusions

Tumbled banded agate beads

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

Aquamarine

Beryl (Be3Al2Si6O18)

Amethyst bead bracelet

Amethyst, purple quartz (SiO₂)

Dyed red crystal aggregate, likely quartz or salt

Uncertain; possibly dyed quartz (SiO₂) or halite (NaCl)

Quartz-rich rock fragment (tentative)

Quartz, silicon dioxide (SiO₂), possibly in a weathered host rock

Tumbled pink feldspar (likely moonstone or orthoclase)

Potassium feldspar, chiefly orthoclase (KAlSi₃O₈); possibly adularescent moonstone

Unidentified dark, flat specimen

Indeterminate; image resolution is insufficient for mineral identification

Dyed Agate

Silicon dioxide, SiO2

Polished orbicular jasper (likely ocean jasper)

Jasper, a microcrystalline variety of quartz (SiO₂), with iron-oxide and other mineral inclusions

Tumbled brown jasper (likely brecciated or scenic jasper)

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

Iron-oxide-stained rock, possibly limonite-rich ore

Likely limonite/goethite-rich material; exact identification requires testing

Opalite (likely man-made glass)

Opalite; amorphous silica glass, not a natural mineral

Green cabochon gemstone pendant, likely turquoise or dyed green turquoise

Probably turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; exact identification requires testing

Satin Spar (Satin Spar Gypsum)

Calcium Sulfate Dihydrate (CaSO4·2H2O)

Heat-Treated Amethyst (Commercial Citrine)

Silicon Dioxide (SiO2) - Macro-crystalline Quartz

Petrified Coral (Agatized Coral)

Fossilized Anthozoa (Silicon Dioxide replacement - SiO2)

Blue Onyx (Dyed Agate/Chalky Chalcedony)

Silicon Dioxide (SiO2) with artificial pigment

Dyed Agate

Silicon Dioxide (SiO2) with artificial pigment

Red coral beads (likely dyed or treated coral)

Corallium spp. (precious coral; calcium-carbonate skeleton, chiefly calcite)

Cassiterite (Tin Ore)

Cassiterite (Tin(IV) Oxide, SnO2)

Iridescent bismuth crystal

Bismuth (Bi), artificially crystallized

Likely scoria (vesicular basalt)

Scoria, typically basaltic; composed mainly of plagioclase, pyroxene, and sometimes olivine

Gold-bearing quartz in a dark host rock (possible gold-in-quartz specimen)

Quartz (SiO₂) with possible native gold (Au) in a fine-grained host; exact identification is uncertain from the photo

Selenite (satin-spar gypsum)

Gypsum, CaSO₄·2H₂O; fibrous variety commonly called satin spar

Transit Token (RTD Denver)

Nickel-plated brass or bronze alloy (Cu-Sn-Zn-Ni)

Dyed Chalcedony (Agate)

Silicon Dioxide (SiO2) with artificial pigment

Heat-Treated Citrine (Amethyst-based)

Quartz (Silicon Dioxide) - SiO2

Milky quartz with iron staining

Quartz (silicon dioxide, SiO₂), likely massive or vein quartz

Likely native silver

Native silver (Ag); identification is provisional from the photo

Likely bismuth crystal

Synthetic bismuth (Bi), crystallized from molten metal; not a natural rock-forming specimen

Celestine (Celestite)

Celestine (Strontium Sulfate, SrSO4)

Copper Ore

Mixed copper sulfides/oxides in gangue matrix

Dyed, polished stone beads (likely assorted agate or jasper)

Microcrystalline quartz, SiO₂ (chalcedony; exact stones cannot be determined from the image)

Copper-bearing rock, likely native copper in a matrix

Native copper (Cu), possibly with cuprite/malachite in a basaltic or porphyritic matrix

Clear quartz (rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

Chrysocolla-rich copper ore

Chrysocolla, a hydrated copper silicate; composition is variable and commonly mixed with quartz or copper oxides

Lepidolite in Quartz Matrix

K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2

Iron Meteorite

Ferriferous Meteorite (Iron-Nickel Alloy)

Iron Meteorite

Iron-Nickel Alloy (Kamacite and Taenite)