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)

Stilpnomelane - (K,Na,Ca)_0,6(Mg,Fe²⁺,Fe³⁺)₆Si₈Al(O,OH)₂₇ * 2-4H₂O

It was first described in 1827 by Ernst Friedrich Glocke for an occurrence in Moravia in the Czech Republic; the name is derived from the Greek "stilpnos" ("shining"), and "melanos" ("black"), alluding to its appearance. Stilpnomelane is a common mineral in low-grade metagreywackes and blueschist-facies rocks, as well as in metamorphosed iron formations.

Optical Properties

• Form: Flaky, radiating and brush-like acicular crystals.
• Color: Yellowish, greenish and brownish with strong pleochroism.
• Interference colors: From II order to III order, but are masked by the color of the mineral.

Black platy Radiating stilpnomelane crystals associated with quartz, Blanchard Mountain, Skagit County, Washington, USA. From RRUFF.

Black platy stilpnomelane crystals associated with quartz, Brunsjo mine, Grythyttan, Vastmanland, Sweden. From RRUFF.

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

Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)
Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)
Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)
Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals (brown) in a blueschist. PPL image, 10x (Field of view = 2mm)
Flaky, Radiating stilpnomelane crystals in a Blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals in a Blueschist. PPL image, 2x (Field of view = 7mm)	Flaky, Radiating stilpnomelane crystals in a Blueschist. PPL image, 2x (Field of view = 7mm)
Flaky, Radiating stilpnomelane crystals in a Blueschist. PPL image, 2x (Field of view = 7mm)	Flaky, Radiating stilpnomelane crystals in a Blueschist. PPL image, 2x (Field of view = 7mm)	Flaky, Radiating stilpnomelane crystals in a Blueschist. XPL image, 2x (Field of view = 7mm)
Flaky, Radiating stilpnomelane crystals in a Blueschist. PPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals in a Blueschist. XPL image, 10x (Field of view = 2mm)	Flaky, Radiating stilpnomelane crystals in a Blueschist. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. XPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. XPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. XPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. XPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. XPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. XPL image, 2x (Field of view = 7mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 2x (Field of view = 7mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals. Laytonville quarry, California. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. XPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. XPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. XPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. XPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)
Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. XPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)	Radiating stilpnomelane crystals in a quartzite. Tyrol, Italy. PPL image, 10x (Field of view = 2mm)