Sedimentary Rock (Altered)

Likely basalt (possibly weathered volcanic rock)

Basalt; predominantly plagioclase feldspar and pyroxene, with possible olivine and iron oxides

Dark mafic rock, likely altered basalt or gabbro

Fine- to medium-grained mafic silicate rock; probable basaltic composition with plagioclase and pyroxene, possibly chloritized/serpentinized

Jasper

Silicon dioxide (SiO2)

Weathered foliated metamorphic rock, likely schist or gneiss

Micaceous schist/gneiss; composition likely quartz, feldspar, mica, and altered mafic minerals

Small brown mineral fragment, possibly quartz/chert

Uncertain; likely microcrystalline quartz (SiO₂) or a weathered silicate rock

Greenstone (Prase / Metavolcanic)

Metamorphosed volcanic rock (Greenstone)

Greenstone, likely chlorite-rich schist

Chlorite schist; chiefly chlorite, actinolite/amphibole, feldspar, and quartz

Lapis Lazuli

Lazurite-rich metamorphic rock (complex silicate)

Epidote

Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Tumbled greenish-gray stone, likely serpentinite or altered basalt

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

Unakite (likely epidote–feldspar rock)

Epidote–K-feldspar–quartz aggregate; commonly approximated as pink orthoclase/microcline + green epidote + quartz

River Cobble (likely Metasedimentary or Basalt)

Metamorphosed Siltstone or Altered Fine-grained Igneous Rock

Weathered granitic rock

Granite or granodiorite; primarily quartz (SiO₂), feldspar, and mica

Lapis Lazuli

Lapis Lazuli (Mineral composition: Lazurite, Calcite, Sodalite, and Pyrite)

Lapis Lazuli

Lapis Lazuli (Complex silicate rock containing Lazurite (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2, Calcite, and Pyrite)

Lapis Lazuli (Low Grade)

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

Lapis Lazuli (polished cabochon)

Lazurite-rich metamorphic rock (approx. Na6Ca2Al6Si6O24(SO4,S,Cl)2)

Blue quartz-bearing rock, possibly chrysocolla-bearing quartzite

Quartz (SiO₂), with probable blue chrysocolla or copper-bearing clay minerals; exact identification requires testing

Polished quartz-rich breccia

Quartz–feldspar breccia; predominantly SiO₂ with feldspar and iron-oxide minerals

Tumbled yellow jasper or iron-stained quartzite

Microcrystalline quartz (SiO₂), likely jasper/quartzite with iron-oxide staining

Orbicular jasper / brecciated jasper slab

Silicified volcanic rock composed mainly of microcrystalline quartz (SiO₂), with iron-oxide and possible chalcedony/agate bands

Milky quartz with iron-oxide staining and dark matrix

Quartz (SiO₂), likely with hematite/goethite and minor feldspar or mica

Veined quartz-bearing metamorphic rock

Likely quartzite or siliceous schist with iron-oxide staining

Quartz (Milky or Smoky variant)

Silicon Dioxide (SiO2)

Lapis Lazuli

Lazurite-dominant Metamorphic Rock (complex aluminosilicate)

Lapis Lazuli

Lapis Lazuli (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Serpentinite (probable)

Serpentinite; chiefly serpentine-group minerals, commonly lizardite, chrysotile, or antigorite, with possible magnetite and relict olivine/pyroxene

Weathered granite or granitic gneiss

Quartz–feldspar–mica rock; likely granitoid, possibly weakly gneissic

Quartz-bearing altered rock, possibly iron-stained quartz vein

Quartz (SiO₂) in a feldspathic/sericitized host, with iron-oxide staining

Polished pegmatitic granite (likely graphic granite)

Coarse-grained granitic rock composed chiefly of quartz, feldspar, and biotite/hornblende

Weathered river stones, likely basaltic andesite and related volcanic rocks

Fine-grained mafic/intermediate volcanic rocks; commonly basalt (plagioclase + pyroxene ± olivine) or andesite (plagioclase + pyroxene ± amphibole)

Copper-bearing rock, likely chrysocolla–malachite with limonite

Chrysocolla (hydrated copper aluminosilicate) and malachite (Cu₂CO₃(OH)₂), with iron oxides and possible native copper

Tumbled epidote-bearing rock (likely epidote–quartz–feldspar aggregate)

Epidote-rich metamorphic rock; minerals likely epidote (Ca₂(Al,Fe)₃Si₃O₁₂(OH), quartz, feldspar, and dark amphibole/biotite)

River Pebble (Granite/Gneiss)

Granitic Pebble (Quartz, Feldspar, Mica composition)

Rounded greenish river pebble

Likely altered basalt or greenstone (metabasalt); exact identification requires testing

Orbicular jasper (likely brecciated jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and silica-rich clasts

Red jasper (likely polished/chipped fragment)

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

Likely weathered iron-rich rock

Probable basalt or limonite/goethite-stained mafic rock; exact identification requires testing

Milky quartz-rich rock

Quartz (silicon dioxide, SiO₂), likely with mica or feldspar inclusions

Gneiss

Gneiss

Polished granite pebble

Granite; chiefly quartz, feldspar, and mica/amphibole

Jasper

Silicon dioxide (SiO2) microcrystalline quartz