Metamorphic Or Igneous Alteration

Unakite Jasper / Unakite

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)

Tumbled brown quartzite or chert

Quartzite, predominantly microcrystalline quartz (SiO₂); exact identification is uncertain from an image

Dragon Blood Jasper

Epidote with Red Jasper inclusions (SiO2 and Ca2(Al,Fe)3(SiO4)3(OH))

Rounded greenish river pebble

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

Granite with Orthoclase and Hematite Staining

Phaneritic Felsic Igneous Rock (primarily SiO2 with KAlSi3O8)

Diabase (Greenstone Pebble)

Diabase or Dolerite

Magnetite

Magnetite (Fe3O4)

Greenstone / altered basalt (likely serpentinite or chlorite-rich rock)

Chlorite–actinolite schist or weakly metamorphosed basalt; exact identification requires testing

Unakite

Granite composed of pink orthoclase feldspar, green epidote, and colorless quartz

Weathered rhyolite or felsic volcanic rock

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

Tumbled greenstone / serpentinite (probable)

Serpentinite, chiefly Mg-rich serpentine minerals (antigorite, lizardite, chrysotile), possibly mixed with chlorite, magnetite, or carbonate

Pale greenish stone, likely serpentine or altered ultramafic rock

Serpentinite (主要 minerals: antigorite/lizardite, Mg3Si2O5(OH)4); identification is tentative from the image

Unakite / Red Jasper beach pebble

Altered Granite (Epidotized Feldspar and Quartz)

Bronzite

(Mg,Fe)SiO3

Basalt (Greenstone)

Amygdaloidal Basalt / Chloritized Basalt

Basalt (Greenstone)

Basalt with chlorite/epidote (often referred to as Greenstone)

Vesicular basalt (weathered basaltic cobble)

Basalt; primarily plagioclase, pyroxene, and olivine

Weathered feldspar-rich granite or granitic pegmatite

Altered granite/pegmatite, composed mainly of quartz (SiO₂), alkali feldspar, plagioclase, and dark mica or amphibole

Biotite-bearing granite or granitic pegmatite fragment

Granite/pegmatite; quartz (SiO₂), feldspar, and biotite mica

Weathered granite pebble

Granitic rock, chiefly quartz, potassium feldspar, plagioclase, and mica/hornblende

Pink Granite

Phaneritic Igneous Rock (high K-feldspar content)

Amygdaloidal Basalt with Epidote/Chlorite

Basalt (containing (Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH)))

Tumbled serpentine

Serpentinite; chiefly antigorite, lizardite, and/or chrysotile [Mg₃Si₂O₅(OH)₄]

Tumbled black-and-gold tiger’s-eye

Quartz pseudomorph after crocidolite; SiO₂ with iron oxides

Tumbled dark green stone, likely serpentine or greenstone

Serpentinite (hydrated magnesium silicate minerals, chiefly antigorite/lizardite); possible chlorite-rich greenstone

Serpentinized ultramafic rock (serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chromite, talc, and carbonate

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)

Greenstone / Diorite

Intermediate plutonic igneous rock

Dyed blue tumbled stone, likely howlite or magnesite

Howlite (Ca₂B₅SiO₉(OH)₅) or magnesite (MgCO₃), artificially dyed blue

Tumbled sodalite with white calcite veining

Sodalite, Na8(Al6Si6O24)Cl2, commonly intergrown with calcite, CaCO3

Serpentinite (likely chlorite–serpentine rock)

Serpentinite; primarily serpentine-group minerals [Mg3Si2O5(OH)4], with possible chlorite, talc, magnetite, and carbonate

Tumbled pale greenish stone, likely serpentine or altered limestone

Probable serpentine-group rock (antigorite/lizardite), possibly serpentinite; identification is visual only

Peridotite (Dunite)

Peridotite (comprising mainly Olivine)

Tumbled Serpentinite and Rose Quartz

Serpentine group (Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4 and Quartz (SiO2)

Quartz-rich granitic rock, possibly pegmatite

Granite/pegmatitic granite; chiefly quartz (SiO₂), feldspar, and mica

Epidote-bearing basalt

Basalt with epidote-group mineral inclusions, likely epidote or pistachite (Ca₂(Al,Fe³⁺)₃(SiO₄)₃(OH))

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)

Weathered granitic rock (tentative)

Granite, composed mainly of quartz, feldspar, and mica

Demitasse Granite (Diorite-Granite transition)

Intermediate Plutonic Rock (Granodiorite/Diorite mix)

Fine-grained gray-green rock, likely basaltic or volcanic stone

Probable basalt or microcrystalline mafic igneous rock; exact identification requires a fresh surface and testing

Tumbled serpentinite (likely)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with dark magnetite/chromite and pale carbonate or talc veins