Metamorphic (Altered Igneous Rock)

Porphyritic basalt or weathered volcanic rock

Basalt, likely plagioclase–pyroxene rock with possible olivine; exact identification requires testing

Reddish iron-rich pebble, possibly jasper or altered basalt

Likely hematite/goethite-bearing basalt or ferruginous jasper; exact identification requires testing

Quartz vein in dark host rock

Quartz (SiO₂), likely in basalt, gabbro, or altered mafic rock

Rounded greenstone cobble

Likely altered basalt/greenstone; commonly chlorite–actinolite–epidote rich

Weathered greenish-brown rock, likely serpentinized ultramafic rock

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with olivine, pyroxene, magnetite, or carbonate

Tumbled greenstone/serpentine pebble

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with chlorite or talc

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Greenish weathered volcanic rock, likely altered basalt

Altered basalt/mafic volcanic rock; green coloration may reflect chlorite, epidote, or celadonite

Weathered vesicular basalt (likely amygdaloidal basalt)

Basalt, chiefly plagioclase + pyroxene ± olivine; cavities may contain secondary zeolites, calcite, or chlorite

Copper-bearing altered rock, likely chrysocolla-bearing quartzite or breccia

Quartz (SiO₂) with copper silicate minerals, chiefly chrysocolla [approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O], and iron oxides

Greenstone (likely altered basalt or metabasalt)

Chlorite–actinolite-rich metabasalt; composition commonly dominated by chlorite, actinolite, epidote, albite, and quartz

Lapis Lazuli (Tumbled Stone)

Na6Ca2(Al6Si6O24)(SO4,S,Cl)2 (predominantly Lazurite)

Quartz vein rock

Milky quartz (SiO₂) in altered host rock, likely quartz-bearing hydrothermal breccia

Polished greenstone pebble (likely epidote-bearing stone)

Epidote–chlorite amphibolite or altered basalt; composition likely epidote, chlorite, amphibole/pyroxene, and iron oxides

Pink Granite (Unakite-bearing Granite Pebble)

Granite (rich in Potassium Feldspar / Orthoclase)

Citrine Quartz

Silicon dioxide (SiO2)

Weathered granite-like rock

Granite or granodiorite; quartz–feldspar–mica aggregate

Tumbled greenish-gray stone, likely serpentinite or altered basalt

Probable serpentinite (serpentine-group minerals), possibly chlorite-/epidote-bearing basalt

Serpentine-rich rock, possibly chrysotile serpentine

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, brucite, or talc

Serpentine (likely serpentinized ultramafic rock)

Serpentinite; chiefly antigorite, lizardite, or chrysotile Mg₃Si₂O₅(OH)₄, often with magnetite and relict olivine/pyroxene

Weathered porphyritic volcanic rock (likely andesite or basalt)

Aphanitic to porphyritic andesite–basalt; composition commonly plagioclase, pyroxene, and minor iron oxides

Weathered igneous rock, likely basaltic lava (uncertain)

Fine-grained mafic volcanic rock, probably basalt; exact identification requires testing

Lapis Lazuli

Lapis Lazuli (A complex rock primarily composed of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Copper-bearing basalt or volcaniclastic rock

Cuprite–malachite-bearing mafic volcanic rock; likely basalt with copper sulfides/oxides

Weathered vesicular basalt

Basalt, a mafic volcanic rock composed mainly of plagioclase feldspar, pyroxene, and commonly olivine

Milky quartz with dark mineral veins

Quartz, silicon dioxide (SiO₂), likely massive vein quartz; dark veins may be chlorite, mica, iron/manganese oxides, or a sulfide mineral

Unakite (likely)

Unakite; epidote–K-feldspar–quartz rock

Likely rose quartz-bearing pegmatite

Quartz-rich pegmatite, principally SiO₂; exact identification is uncertain from the photograph

Serpentinite (likely veined variety)

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

Polished porphyritic volcanic rock (likely rhyolite or andesite)

Porphyritic rhyolite–andesite; fine volcanic groundmass with abundant pale feldspar phenocrysts and possible vesicles

Iron-rich jasper (likely brecciated jasper)

Microcrystalline quartz/chalcedony (SiO₂) colored by hematite/goethite; possibly iron formation

Weathered copper-bearing rock (likely malachite-stained basalt or greenstone)

Malachite, Cu₂CO₃(OH)₂, as a secondary coating on a mafic host rock; exact identification requires testing

Unakite (likely, rough specimen)

Epidote–feldspar–quartz rock; commonly approximated as pink orthoclase + green epidote + quartz

Porphyritic volcanic rock, likely porphyritic andesite

Porphyritic andesite; chiefly plagioclase and pyroxene/amphibole phenocrysts in a fine volcanic groundmass

Weathered dark igneous rock, likely basalt

Basalt; primarily plagioclase feldspar and pyroxene, commonly with olivine and iron oxides

Unakite

Epidote–orthoclase–quartz metamorphic rock

Weathered granite or granitic gneiss

Granite; primarily quartz, feldspar, and mica (possibly foliated as gneiss)

Serpentinized ultramafic rock with magnesite

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with likely magnesite (MgCO₃) and minor chromite/magnetite

Pink feldspar-rich granite or pegmatite

Potassium-feldspar granite; chiefly microcline/orthoclase (KAlSi₃O₈), quartz, and minor mica

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, possibly altered granite

Weathered green-gray stone, likely serpentinite or chlorite-rich metamorphic rock

Probable serpentinite (antigorite–lizardite), possibly chlorite schist or altered basalt

Weathered greenish metamorphic rock, likely serpentinite

Serpentinite, dominated by serpentine-group minerals (commonly antigorite, lizardite, or chrysotile)