Rock Identifier

Category

Metamorphic Or Igneous Alteration

Browse metamorphic or igneous alteration specimens identified by the Rock Identifier community.

Learn about Metamorphic Or Igneous Alteration in the encyclopedia

Cordierite Hornfels

Cordierite Hornfels

Migmatite

Talc-carbonate Rock

Talc-carbonate Rock

Hornblende Schist

Hornblende Schist

Epidosite

Oregon Opal

Orendite

Orthoclase

Orca Agate

Orange Opal

Peacock Ore

Orange Garnet

Raw Emerald in Matrix (Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities) — mineral

Raw Emerald in Matrix

Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities

Black Onyx (Silicon Dioxide (SiO2) with parallel banding) — mineral

Black Onyx

Silicon Dioxide (SiO2) with parallel banding

Blue-gray feldspar-rich rock, likely labradorite-bearing gneiss or anorthosite (Plagioclase feldspar (albite–anorthite series), possibly with labradorite; exact rock identification is uncertain from one photo) — metamorphic

Blue-gray feldspar-rich rock, likely labradorite-bearing gneiss or anorthosite

Plagioclase feldspar (albite–anorthite series), possibly with labradorite; exact rock identification is uncertain from one photo

Fine-grained green-gray rock pebble, likely basalt or greenstone (Probable basalt (plagioclase and pyroxene), possibly altered to greenstone) — igneous

Fine-grained green-gray rock pebble, likely basalt or greenstone

Probable basalt (plagioclase and pyroxene), possibly altered to greenstone

Polished green stone, likely serpentine or nephrite jade (Serpentine-group minerals, chiefly antigorite/lizardite; possible nephrite (actinolite–tremolite amphibole)) — metamorphic

Polished green stone, likely serpentine or nephrite jade

Serpentine-group minerals, chiefly antigorite/lizardite; possible nephrite (actinolite–tremolite amphibole)

Bull Quartz (Milky Quartz) (Silicon Dioxide (SiO2)) — mineral

Bull Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Yellow Sapphire (Corundum (Al2O3)) — mineral

Yellow Sapphire

Corundum (Al2O3)

Serpentine (Serpentinite (Mg,Fe,Ni,Al,Zn)3Si2O5(OH)4) — metamorphic

Serpentine

Serpentinite (Mg,Fe,Ni,Al,Zn)3Si2O5(OH)4

Seraphinite (Clinochlore) (Clinochlore (Mg,Fe2+)5Al(Si3Al)O10(OH)8) — mineral

Seraphinite (Clinochlore)

Clinochlore (Mg,Fe2+)5Al(Si3Al)O10(OH)8

Epidote (Epidote (Ca2(Al2,Fe3+)3(SiO4)3(OH))) — metamorphic

Epidote

Epidote (Ca2(Al2,Fe3+)3(SiO4)3(OH))

Cloud Quartz (Milky Quartz) (Silicon Dioxide (SiO2)) — mineral

Cloud Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Dragon Blood Jasper (Epidote with Red Piedmontite (silicate)) — sedimentary

Dragon Blood Jasper

Epidote with Red Piedmontite (silicate)

Gold Nugget (Native Gold (Au)) — mineral

Gold Nugget

Native Gold (Au)

Red glass-like crystal, likely synthetic ruby or red glass (Uncertain from image; possible corundum (ruby), Al₂O₃, or synthetic glass) — gemstone

Red glass-like crystal, likely synthetic ruby or red glass

Uncertain from image; possible corundum (ruby), Al₂O₃, or synthetic glass

Green Quartz / Prasiolite (Silicon Dioxide (SiO2)) — mineral

Green Quartz / Prasiolite

Silicon Dioxide (SiO2)

Yellow Sapphire (Corundum (Al2O3:Fe)) — gemstone

Yellow Sapphire

Corundum (Al2O3:Fe)

Weathered gray-green pebble (Indeterminate; possibly altered basalt, serpentinite, or a greenish metamorphic rock) — mineral

Weathered gray-green pebble

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

Nephrite Jade (Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)) — metamorphic

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Ruby (Pinkish-Red) (Corundum (Al2O3 with Chromium trace)) — mineral

Ruby (Pinkish-Red)

Corundum (Al2O3 with Chromium trace)

Greenstone (Chert) (Microcrystalline Silica (SiO2) with chlorite/epidote inclusions) — metamorphic

Greenstone (Chert)

Microcrystalline Silica (SiO2) with chlorite/epidote inclusions

Quartz Vein on Matrix (Silicon Dioxide (SiO2)) — mineral

Quartz Vein on Matrix

Silicon Dioxide (SiO2)

Yellow Quartz (Citrine/Yellow Jasper mix) (Silicon Dioxide (SiO2)) — mineral

Yellow Quartz (Citrine/Yellow Jasper mix)

Silicon Dioxide (SiO2)

Gold-bearing dark rock, possibly magnetite with iron-oxide staining (Likely magnetite (Fe₃O₄) with limonite/goethite; metallic patches may be gold or weathered sulfide, unconfirmed) — mineral

Gold-bearing dark rock, possibly magnetite with iron-oxide staining

Likely magnetite (Fe₃O₄) with limonite/goethite; metallic patches may be gold or weathered sulfide, unconfirmed

Tumbled serpentine (likely) (Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄) — metamorphic

Tumbled serpentine (likely)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄

Blue Sapphire (Corundum (Al2O3)) — gemstone

Blue Sapphire

Corundum (Al2O3)

Yellow Aventurine (Quartz (SiO2) with inclusions) — mineral

Yellow Aventurine

Quartz (SiO2) with inclusions

Rough Gemstone Grains (Mixed Sapphires and Quartz) (Corundum (Al2O3) and Quartz (SiO2)) — mineral

Rough Gemstone Grains (Mixed Sapphires and Quartz)

Corundum (Al2O3) and Quartz (SiO2)

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Gold Ore in Matrix (Native Gold (Au) in Quartz/Host Rock) — mineral

Gold Ore in Matrix

Native Gold (Au) in Quartz/Host Rock

Gold Ore (Native Gold (Au) in Matrix) — mineral

Gold Ore

Native Gold (Au) in Matrix

Foliated metamorphic rock, likely gneiss (Biotite–quartz–feldspar gneiss, possibly migmatitic gneiss) — metamorphic

Foliated metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss, possibly migmatitic gneiss

Lapis Lazuli (Lapis Lazuli (Complex rock primarily composed of Lazurite (Na,Ca)8[(SO4,S,Cl)2|(AlSiO4)6], Calcite, and Pyrite)) — metamorphic

Lapis Lazuli

Lapis Lazuli (Complex rock primarily composed of Lazurite (Na,Ca)8[(SO4,S,Cl)2|(AlSiO4)6], Calcite, and Pyrite)

Weathered granite (likely with accessory quartz) (Granite; chiefly quartz, K-feldspar, plagioclase, and biotite/hornblende) — igneous

Weathered granite (likely with accessory quartz)

Granite; chiefly quartz, K-feldspar, plagioclase, and biotite/hornblende

Epidote in Quartz (Epidote (Ca2(Al2,Fe3+)3(SiO4)3(OH)) / Quartz (SiO2)) — metamorphic

Epidote in Quartz

Epidote (Ca2(Al2,Fe3+)3(SiO4)3(OH)) / Quartz (SiO2)

Milky quartz (Quartz (silicon dioxide, SiO₂)) — mineral

Milky quartz

Quartz (silicon dioxide, SiO₂)

Quartz with Mafic/Chlorite Veins (Silicon Dioxide (SiO2) with Chlorite/Epidote cross-veining) — metamorphic

Quartz with Mafic/Chlorite Veins

Silicon Dioxide (SiO2) with Chlorite/Epidote cross-veining

Milky Quartz Vein in Host Rock (Silicon Dioxide (SiO2)) — Mineral

Milky Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

Quartz with Pyrite (Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)) — mineral

Quartz with Pyrite

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)

Milky Quartz (Quartz (Silicon Dioxide - SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Unakite (Epidotized Granite) — metamorphic

Unakite

Epidotized Granite

Serpentine (Antigorite, Lizardite, or Chrysotile (Mg, Fe)3Si2O5(OH)4) — metamorphic

Serpentine

Antigorite, Lizardite, or Chrysotile (Mg, Fe)3Si2O5(OH)4

Emerald (Beryl (Be₃Al₂(SiO₃)₆) with Chromium or Vanadium impurities) — mineral

Emerald

Beryl (Be₃Al₂(SiO₃)₆) with Chromium or Vanadium impurities