Metamorphic (Altered Igneous Rock)

Weathered gray rock, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; likely basalt (plagioclase ± pyroxene, possibly altered)

Quartz-bearing rock, possibly weathered granite or pegmatite

Quartz–feldspar–mica aggregate; exact classification is uncertain from the image

Unakite

Granite (altered hydrothermal)

Tumbled greenstone (likely serpentine or chlorite-rich metamorphic rock)

Serpentinite, approximately Mg₃Si₂O₅(OH)₄, or chlorite-rich greenstone

Weathered quartz-rich rock fragment

Indeterminate; likely altered granite or quartz-bearing pegmatite

Polished red gemstone pendant, likely red jasper or brecciated jasper

Jasper: microcrystalline quartz (SiO₂), commonly with hematite or iron-oxide inclusions

Weathered iron-rich volcanic rock

Likely altered basalt or andesite with iron-oxide staining

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-like jasper / epidote–feldspar rock

Epidote–feldspar–quartz aggregate; commonly marketed as unakite or brecciated jasper

Likely chlorite schist or altered mafic rock

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

Turquoise

Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Tumbled pink feldspar-rich granite (likely potassium feldspar)

Granite/pegmatitic feldspar aggregate; chiefly KAlSi₃O₈ with quartz and minor mica or iron oxides

Weathered volcanic rock, likely andesite

Andesite (plagioclase–pyroxene volcanic rock), identification tentative

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

Polished labradorite

Labradorite, calcium-sodium feldspar: (Ca,Na)(Al,Si)₄O₈

Weathered granite or granitic gneiss pebble

Granite; chiefly quartz (SiO₂), feldspar, and mica; possibly weakly gneissic

Weathered quartz-rich pebble

Likely altered granite or granitic gneiss; chiefly quartz and feldspar with minor mica/iron oxides

Tumbled dark stone, likely basalt or basaltic pebble

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

Unakite

Altered Granite (Epidotized Granite)

Coarse-grained granite

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

Polished river stone, likely serpentinite or altered ultramafic rock

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

Tumbled greenstone / altered basalt pebble

Fine-grained mafic volcanic rock, likely basalt or greenstone; commonly composed of plagioclase, pyroxene, chlorite, epidote, and iron oxides

Epidote

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

Polished Picasso jasper

Silicified carbonate rock, commonly marketed as Picasso jasper; composition varies and is not a single mineral species

Epidote in Matrix (likely Amphibolite or Gneiss)

Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH)) in Metamorphic Matrix

Quartz-rich pegmatite or quartz vein rock

Mostly quartz (SiO₂), with probable feldspar and iron-oxide staining

Weathered basalt or mafic volcanic rock

Basalt; predominantly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Black Star Diopside (beads)

Diopside (CaMgSi2O6) - a member of the pyroxene group

Sodalite

Sodalite (Na8Al6Si6O24Cl2)

Unakite (polished/tumbled)

Unakite, a hydrothermally altered granite composed mainly of epidote, pink potassium feldspar (orthoclase/microcline), and quartz

Greenstone (likely serpentinite or chlorite-rich metamorphic rock)

Probable serpentinite/chlorite schist; commonly dominated by serpentine-group minerals, chlorite, talc, and magnetite

Weathered rhyolite or felsic volcanic rock

Rhyolite, commonly quartz–alkali feldspar–plagioclase with iron-oxide alteration

Dendritic limestone or marble slab

Manganese-oxide dendrites in carbonate rock, likely calcite (CaCO₃)

Unakite

Metamorphosed Granite (Orthoclase, Epidote, Quartz)

Tiger's Eye and Gemstone Assortment

Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions)

Weathered basalt or iron-rich volcanic rock

Mafic volcanic rock, likely basalt; exact identification requires testing

Tumbled green epidote–quartz (probable)

Epidote, Ca₂(Al,Fe³⁺)₃(SiO₄)₃(OH), likely intergrown with quartz and/or chlorite

Weathered granitic or gneissic cobble

Likely altered granite/granodiorite; exact identification requires a fresh surface and testing

Tiger's Eye (Brown/Golden)

Silicon dioxide (Quartz pseudomorph after crocidolite), SiO2

Tumbled pegmatitic granite

Granite, chiefly quartz–feldspar–mica; likely altered pegmatite

Fuchsite or Green Mica Schist

Muscovite variant (KAl2(AlSi3O10)(OH)2 with Cr)