Metamorphic (Altered Igneous Rock)

Chlorite-rich schist (probable greenschist)

Greenschist-facies metabasalt or chlorite–actinolite schist

Tumbled green stone, likely serpentine

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

Likely basaltic rock or mafic metamorphic specimen

Basalt, possibly altered to amphibolite/greenstone; chiefly plagioclase and pyroxene, with possible chlorite, amphibole, and iron oxides

Green Andesite (or Greenstone / Altered Volcanic Rock)

Intermediate Volcanic Rock with Chlorite/Epidote Alteration

Black-veined pebble, likely basalt in a weathered host rock

Probable basaltic dike or vein in altered volcanic rock; exact identification requires testing

Calcite-rich marble or limestone

Calcite (CaCO₃), likely recrystallized limestone (marble)

Greenstone pebble, likely altered basalt

Metabasalt/greenstone; commonly chlorite–epidote–actinolite with albite and iron oxides

Copper-bearing volcanic breccia

Altered andesite or rhyolite breccia with secondary copper minerals, likely chrysocolla and/or malachite

Weathered quartz-rich rock, possibly granite or pegmatite fragment

Uncertain; likely quartz–feldspar aggregate, potentially granitic pegmatite

Unakite (Epidote-Rich Granite)

Unakite (Granite consisting of Orthoclase, Quartz, and Epidote)

Iron-rich rock fragment, possibly weathered hematite-bearing basalt

Likely basalt with iron oxides/hydroxides; composition may include hematite (Fe₂O₃) or goethite (FeO(OH))

Banded greenstone or altered basalt

Chlorite–epidote amphibolite/greenstone; exact identification requires testing

Unakite

Unakite (Altered Granite)

Weathered igneous pebble, likely basaltic andesite

Fine-grained mafic to intermediate volcanic rock; chiefly plagioclase feldspar, pyroxene, and possibly olivine or magnetite

Serpentinite with carbonate and iron-oxide alteration

Serpentinite; chiefly antigorite/lizardite Mg₃Si₂O₅(OH)₄, with magnetite, calcite, and chromian minerals

Weathered volcanic rock, likely altered basalt

Basaltic rock, probably chlorite–epidote–iron-oxide altered basalt

Tumbled dalmatian jasper (likely)

Microcrystalline quartz/chalcedony with black amphibole or aegirine inclusions; commonly sold as “dalmatian jasper”

Orbicular jasper / brecciated jasper

Silica-rich microcrystalline quartz (chalcedony), commonly with iron oxides and altered volcanic fragments

Polished jasper pebble

Jasper, microcrystalline quartz (SiO₂) with iron-oxide and clay-mineral impurities

Lapis Lazuli

Lapis lazuli (Complex rock consisting mainly of Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Weathered basaltic volcanic rock

Basalt, likely vesicular/amygdaloidal basalt

Weathered, biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite rock; likely granite (compositionally, quartz + K-feldspar/plagioclase + biotite), possibly weakly foliated gneiss

Lapis Lazuli

Lazurite-rich metamorphic rock (approx. (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Dumortierite (or Blue Dumortierite Quartz / Variscite)

Dumortierite - Al7BO3(SiO4)3O3

Dumortierite (or Dumortierite Quartz)

Dumortierite (Al7BO3(SiO4)3O3)

Mica-rich metamorphic rock, likely mica schist

Muscovite–biotite schist, possibly with garnet and quartz

Tumbled serpentine

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

Weathered vesicular volcanic rock (likely pumice/tuff)

Porous volcanic pyroclastic rock, probably pumiceous tuff; exact identification requires testing

Greenstone / Chert

Cryptocrystalline Quartz (SiO2) or Altered Basalt

Granitic gneiss or weathered granite cobble

Quartz–feldspar–mica rock; likely gneiss (compositionally granite-derived)

Weathered granitic rock (likely granite or granodiorite)

Granite–granodiorite; chiefly quartz, feldspar, and mica

Likely porphyritic basalt or andesite fragment

Fine-grained mafic to intermediate volcanic rock; commonly plagioclase ± pyroxene, amphibole, and iron oxides

Unakite Jasper / Unakite

Altered Granite (containing Epidote, Orthoclase Feldspar, and Quartz)

Likely serpentinite pebble

Serpentinite, composed mainly of serpentine-group minerals (e.g., antigorite or lizardite); identification from the image is uncertain

Banded limestone or marble

Calcite-dominated carbonate rock; likely banded marble (CaCO₃)

Possibly banded ironstone (iron-rich metamorphic rock)

Likely iron formation, composed chiefly of hematite or goethite with silica-rich layers; exact identification is uncertain from the photo

Lapis Lazuli

Lapis Lazuli (Rock containing Lazurite: (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Weathered banded gneiss (probable)

Gneiss; quartz–feldspar–mica metamorphic rock

Weathered granite, possibly pink granite

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Greenstone (Epidosite or Altered Basalt)

Epidosite (Ca2(Al, Fe)3(SiO4)3(OH))

Pale blue-green altered volcanic rock, likely basalt

Altered basalt (fine-grained plagioclase–pyroxene rock with secondary zeolite/chlorite minerals)

Tumbled serpentine (likely antigorite-rich)

Serpentine-group minerals, chiefly Mg₃Si₂O₅(OH)₄