Metamorphic Minerals

• Actinolite
• Alurgite
• Andalusite
• Andalusite (chiastolite)
• Antigorite
• Anthophyllite-Gedrite
• Biotite
• Brucite
• Calcite
• Cassiterite
• Charoite
• Chlorite
• Chloritoid
• Chrysocolla
• Cordierite
• Corundum
• Corundum (ruby)
• Kyanite
• Kornerupine
• Kyanite (reticite)
• Deerite
• Dumortierite
• Epidotes
Allanite
Pistacite
Piemontite
Zoisite

• Fassaite
• Fluorite
• Glaucophane
• Garnet
• Hercynite
• Hedenbergite
• Hydrogrossular
• Howieite
• Humites
• Jadeite
• Lawsonite
• Lazulite
• Lazurite
• Malachite
• Minnesotaite
• Muscovite
• Olivine
• Omphacite
• Omphacite Cr
• Pargasite
• Piemontite (Praborna)
• Pyrite
• Prehnite
• Pumpellyite
• Quartz
• Rhodonite
• Rutile
• Sapphirine
• Scapolite
• Serpentine
• Sillimanite
• Sillimanite (fibrolite)
• Staurolite
• Stilpnomelane
• Sugilite
• Talc
• Taramellite
• Thulite
• Tinaksite
• Tinzenite
• Titanite
• Tremolite
• Tourmaline
• Vesuvianite
• Violan
• Wollastonite
• Yoderite
• Zussmanite

Texture and Microstructure

• Augen
• Book shelf sliding
• Boudinage
• Corona
• Decussate
• Deformation lamellae
• Deformation twins
• Crenulation cleavage
• Fringes
• Granoblastic
• Kelyphite
• Kink Bands
• Lepidoblastic
• Mesh
• Mica fish
• Mylonitic
• Nematoblastic
• Oblique foliations
• Polygonal
• Porphyroblastic
• Porphyroclastic
• Pseudomorph
• Ribbon
• S-C fabric
• Skeletal garnet
• Symplectite
• Veins

Metamorphic Rocks

• Albite greenshist
• Amphibolite (felsic)
• Amphibolite (mafic)
• Amphibolite (mylonitic)
• Amphibolite with epidote
• Andalusite schist
• Anyolite
• Augen gneiss
• Blueschist
• Blueschist (Ile de Groix)
• Blueschist (retrograde)
• Buchite
• Calc-schists
• Carbonated peridotite
• Cataclasite
• Charoitite
• Chlorite schist
• Chloritoid Schist (Ile de Groix)
• Cordierite slate
• Corundum-fuchsite rock
• Deformed oolite
• Dunite (mylonitic)
• Eclogite
• Eclogite Porto Ottiolu
• Epidosite
• Gabbro (mylonitic)
• Garnet micaschist
• Glaucophane granofels
• Granite (mylonitic)
• Granulite (felsic)
• Granulite (mafic)
• Granulite (retrograde)
• Granulite (sapphirine-bearing)
• Greenschist
• Hornfels
• Hornfels (albite-epidote)
• Hornfels (cordierite, plagioclase)
• Hornfels (corundum, plagioclase)
• Hornfels (hydrogarnet)
• Jadeite metagranite
• Jadeitite
• Kinzigite
• Lapis lazuli
• Marble
• Marble (calc-silicate)
• Marble (diopside)
• Marble (forsterite)
• Marble (mylonitic)
• Marble (tremolite)
• Mylonite
• Ocean jasper
• Ophicalcite
• Peridotite (mylonitic)
• Phyllite
• Prasinite
• Pseudotachylyte
• Pseudotachylyte (Ivrea-Verbano)
• Quartzite
• Quartzite (tourmaline)
• Rhyolite (mylonitic)
• Rodingite
• Schist
• Seafloor basalt
• Serpentinite
• Serpentinized lherzolite
• Skarn
• Skiddaw Metamorphic Aureole
Skiddaw
1) Spotted slate
2) Andalusite slate
3) Cordierite slate

• Slate
• Slate (ottrelite)
• Talc schist
• Tourmalinite
• Ultramylonite (granitic)
• Ultramylonite (mafic)

Hercynite - FeAl₂O₄

Hercynite is a spinel that occurs in high-grade metamorphosed iron rich argillaceous sediments as well as in mafic and ultramafic igneous rocks. Due to its hardness it also is found in placers. It was first described in 1847 and its name originates from the Latin name for the Harz, Silva Hercynia, where the species was first found.

Bibliography

• Bucher, K., & Grapes, R. (2011). Petrogenesis of metamorphic rocks. Springer Science & Business Media.
• Fossen, H. (2016). Structural geology. Cambridge University Press.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Passchier, Cees W., Trouw, Rudolph A. J: Microtectonics (2005).
• Philpotts, A., & Ague, J. (2009). Principles of igneous and metamorphic petrology. Cambridge University Press.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.
• Vernon, R. H. (2018). A practical guide to rock microstructure. Cambridge university press.

Photo

Hercynite (green) and biotite crystals. MME (Mafic microgranular enclaves) in the S.Andrea granite. Elba Island, Italy. PPL image, 10x (Field of view = 2mm)	Hercynite (green) and biotite crystals. MME (Mafic microgranular enclaves) in the S.Andrea granite. Elba Island, Italy. PPL image, 10x (Field of view = 2mm)	Hercynite (green) and biotite crystals. MME (Mafic microgranular enclaves) in the S.Andrea granite. Elba Island, Italy. PPL image, 10x (Field of view = 2mm)
Green hercynite crystalss in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystalss in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystalss in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)
Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Hercynite crystalss (isotropic) in a metamorphic xenolith from Vesuvius. XPL image, 10x (Field of view = 2mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)
Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 2x (Field of view = 7mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)
Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)
Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Hercynite crystals (isotropic) in a metamorphic xenolith from Vesuvius. XPL image, 10x (Field of view = 2mm)
Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)
Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 2x (Field of view = 7mm)	Hercynite crystals (isotropic) in association with muscovite and Humites in a metamorphic xenolith from Vesuvius. XPL image, 10x (Field of view = 2mm)
Hercynite crystals enclosed in muscovite in a metamorphic xenolith from Vesuvius. PPL image, 10x (Field of view = 2 mm)	Hercynite crystals enclosed in muscovite in a metamorphic xenolith from Vesuvius. XPL image, 10x (Field of view = 2 mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 2x (Field of view = 7mm)
Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 2x (Field of view = 7mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 2x (Field of view = 7mm)	Green hercynite crystals in a metamorphic xenolith from Vesuvius. PPL image, 2x (Field of view = 7mm)