Sedimentary Rock (Altered)

Red Sandstone with Reduction Spot

Quartzose Sandstone with a Leach/Reduction Spot

Weathered volcanic rock, likely andesite

Andesite (plagioclase–pyroxene volcanic rock), identification tentative

Rounded granitic cobble

Granite or granitic gneiss; primarily quartz, feldspar, and mica

Polished Ocean Jasper

Orbicular jasper (microcrystalline quartz, SiO₂)

Gold-bearing quartz vein rock (likely pyrite-rich quartzite)

Quartz (SiO₂) with iron sulfides, chiefly pyrite (FeS₂), possibly chalcopyrite (CuFeS₂); gold cannot be confirmed visually

Unakite

Altered granite (Epidote, Orthoclase Feldspar, and Quartz)

Polished amber

Amber (fossilized plant resin; chiefly polymerized diterpenoid resin)

Lapis Lazuli

Complex mixture of minerals (lazurite, calcite, pyrite, and sodalite); (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Quartz-bearing metamorphic rock, possibly epidote/quartzite

Quartz-rich rock with possible epidote and feldspar; exact identification requires testing

Weathered feldspathic rock, likely granite or granitic pegmatite

Quartz–feldspar–mica aggregate; exact species indeterminate from the image

Lapis Lazuli

Lapis lazuli (a rock primarily composed of Lazurite, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)

Likely serpentinite or chlorite-rich metamorphic rock

Serpentinite, mainly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with chlorite, magnetite, and carbonates

Weathered iron-rich basalt or volcanic breccia

Mafic volcanic rock, likely basalt; composition dominated by plagioclase and pyroxene with iron oxides

Porous quartz-rich rock, likely weathered rhyolite or silicified volcanic breccia

Rhyolite or volcanic breccia; predominantly microcrystalline quartz (SiO₂) with altered feldspar and iron oxides

Greenstone / Chert

Cryptocrystalline Quartz (SiO2) or Altered Basalt

Tumbled jasper or rhyolitic volcanic rock

Microcrystalline quartz-bearing rhyolite/jasper; commonly quartz (SiO₂), feldspar, and iron-oxide minerals

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, possibly altered granite

Granitoid (with Epidote and Orthoclase)

Crystalline Felsic Intrusive Rock (containing SiO2, KAlSi3O8, and Ca2(Al2,Fe)(Si2O7)(SiO4)O(OH))

Greenstone / Basalt

Aphanitic Mafic Igneous Rock (likely altered Basalt)

Porphyritic volcanic rock (likely rhyolite or andesite)

Porphyritic rhyolite–andesite; fine volcanic groundmass with feldspar and mafic phenocrysts

Weathered porphyritic volcanic rock

Likely andesite or dacite, with feldspar phenocrysts in a fine-grained groundmass

Lapis Lazuli

Sodium aluminum silicate with sulfur (main component: Lazurite [(Na,Ca)8(AlSiO4)6(SO4,S,Cl)2])

Basaltic beach cobble

Fine- to medium-grained basalt, likely locally porphyritic or altered

Tumbled dark stone, likely basalt or basaltic pebble

Fine-grained mafic volcanic rock; commonly composed of plagioclase, pyroxene, and minor olivine (basalt)

Tumbled granite or granitic pebble

Granite; primarily quartz, feldspar, and mica (exact variety uncertain from the image)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Greenstone pebble

Likely chlorite- or epidote-bearing metamafic rock (metabasalt/greenschist)

Tumbled turquoise

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

Tiger's Eye

Quartz pseudomorph after crocidolite (SiO2)

Citrine Geode Fragment

Silicon Dioxide (SiO2) with iron impurities

Weathered quartz-rich rock, likely silicified limestone or quartzite

Microcrystalline quartz (SiO₂), possibly with calcite (CaCO₃) and iron-oxide staining

Serpentinized ultramafic rock with magnesite

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

Flint / Chert

Microcrystalline Quartz (SiO2)

Tumbled greenstone (likely serpentinite or green jasper)

Serpentinite, commonly dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄); exact identification requires testing

Pegmatitic granite (quartz–feldspar–mica rock)

Granitic pegmatite; primarily quartz (SiO₂), alkali/plagioclase feldspar, and minor mica, with iron-oxide staining

Porphyritic basalt (likely olivine basalt)

Basalt; fine-grained plagioclase–pyroxene matrix with possible olivine phenocrysts

Weathered basaltic cobble

Basalt, likely amygdaloidal or vesicular basalt

Weathered gray-green pebble

Indeterminate; possibly altered basalt, serpentinite, or a greenish metamorphic rock

Iron-stained quartz-rich rock, possibly weathered granite or pegmatite

Quartz (SiO₂) with probable feldspar and iron-oxide staining; exact identification is uncertain from the photograph

Unakite (Epidote-Rich Granite)

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

Lapis Lazuli (in jewelry setting)

Na8[Al6Si6O24]n(S,Cl,SO4,OH)2 (Lazurite-rich rock)

Iron-stained quartz-rich rock, possibly goethite-bearing quartz

Quartz (SiO₂) with iron oxides/hydroxides, likely goethite or limonite