Sedimentary Rock (Altered)

Granite (likely biotite granite or granodiorite)

Coarse-grained granitoid composed mainly of quartz, feldspar, and dark biotite/amphibole

Quartz-veined metamorphic rock, likely greenschist or altered basalt

Chlorite–actinolite schist or metabasalt with a milky quartz vein

Polished carnelian

Carnelian, a red-orange variety of chalcedony (microcrystalline quartz, SiO₂)

Polished tiger iron

Tiger iron: banded quartz (SiO₂), red jasper, and crocidolite-derived fibrous iron oxides

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Weathered basalt (likely vesicular basalt)

Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine

Banded chert or siliceous shale

Microcrystalline quartz (SiO₂), possibly interbedded with carbonaceous or clay-rich shale

Pink feldspar-bearing granite or pegmatitic rock

Granite/pegmatite, chiefly quartz (SiO₂), potassium feldspar (KAlSi₃O₈), plagioclase, and dark mica/amphibole; pink areas may be K-feldspar or garnet.

Serpentinized ultramafic rock (probable serpentinite)

Serpentinite, dominated by serpentine-group minerals (lizardite/chrysotile/antigorite), with possible magnetite and carbonate

Lapis Lazuli

Lapis Lazuli (Complex rock containing Sodalite, Lazurite, Calcite, and Pyrite)

Green-and-white quartz-rich rock, likely chrysoprase or serpentine-bearing stone

Uncertain; possible chrysoprase (microcrystalline quartz, SiO₂) or serpentinite (magnesium silicate minerals)

Purpurite

Manganese Iron Phosphate, Mn3+(PO4)

Rounded granitic pebble

Granite, chiefly quartz–feldspar–mica aggregate

Weathered fossiliferous limestone fragment, possibly fossil coral or shell material

Indeterminate carbonate fossil in calcitic limestone; likely composed mainly of calcite (CaCO₃), but species identification is not possible from this image alone

Coarse-grained granite

Granite, chiefly quartz (SiO₂), potassium feldspar, plagioclase, and biotite/hornblende

Granite pebble

Granite; chiefly quartz, potassium feldspar, plagioclase, and minor biotite/hornblende

Unakite (likely)

Epidote–K-feldspar–quartz aggregate; epidote: Ca₂(Al,Fe³⁺)₃Si₃O₁₂(OH)

Tumbled turquoise (probable)

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

Tumbled serpentine

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and carbonate

Unakite

Unakite (Epidote-Feldspar rock)

Raw turquoise

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

Iron-stained quartz-rich rock, likely pegmatite or quartz vein fragment

Quartz (SiO₂) with feldspar, mica, and iron-oxide/hydroxide staining; possibly weathered granite pegmatite

Red Jasper

Jasper (SiO2 with Fe2O3 inclusions)

Weathered purple rhyolite (probable porphyritic volcanic rock)

Rhyolite, commonly quartz–alkali-feldspar–plagioclase with minor biotite or iron oxides

Fossilized Oyster Shell

Gryphaea or Crassostrea fossil (Calcium Carbonate, CaCO3)

Red jasper (likely brecciated jasper)

Jasper, microcrystalline quartz (SiO₂), colored mainly by iron oxides

Likely weathered basalt or dark metamorphic rock

Fine-grained mafic rock, probably basalt (plagioclase + pyroxene ± olivine)

Pink Granite (Unakite-bearing or Epidote-bearing Granite)

Plutonic Igneous Rock (Granite)

Unakite

Epidote–orthoclase–quartz metamorphic rock

Polished/tumbled unakite (probable)

Unakite; epidote + pink potassium feldspar + quartz

Weathered porphyritic pebble

Likely porphyritic volcanic rock, possibly andesite or rhyolite

Likely chlorite schist or altered mafic rock

Chlorite–actinolite schist; commonly composed of chlorite, actinolite/amphibole, epidote, and albite

Polished carnelian

Carnelian, a red-orange variety of chalcedony (microcrystalline quartz, SiO₂)

Weathered quartz-rich rock, possibly granite or gneiss

Granite-like aggregate: quartz (SiO₂), feldspar, and minor dark minerals

Quartz-rich breccia or altered granite fragment

Polymineralic quartz–feldspar rock, likely hydrothermally altered granite/pegmatite

Azurite and Malachite on Matrix

Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2CO3(OH)2

Red jasper with druzy quartz

Jasper (microcrystalline quartz, SiO₂), locally coated or veined with crystalline quartz

Weathered granite or granitic gneiss

Granite; mainly quartz (SiO₂), feldspar, and mica

Porphyritic basalt (likely amygdaloidal basalt)

Basaltic rock dominated by plagioclase feldspar and pyroxene, with possible vesicle-filling zeolite/calcite

Citrine (Heat-treated Amethyst)

Citrine Quartz (SiO2)

Polished river stone, likely serpentinite or altered ultramafic rock

Serpentinite-dominant rock; chiefly serpentine-group minerals, commonly with magnetite, talc, and carbonate

Rounded river cobble, likely basaltic rock

Fine-grained mafic volcanic rock, probably basalt or altered basalt