Staurolite is a silicate mineral with a generalized chemical composition of (Fe,Mg) 2 Al 9 Si 4 O 23 (OH). Facebook. Other index minerals commonly associated with Staurolite: Kyanite. Staurolite's hand sample has characteristic penetration twinning and unique crystal habit. Key optical features of staurolite in thin section: Common minerals that might be confused with staurolite and occur in similar rocks: Oct 2, 2020 - Explore Bryn Mawr College Mineralogy's board "Minerals in Thin Section", followed by 119 people on Pinterest. Rock-forming minerals of metamorphic rocks, in thin section (a work in progress) ... 32 Staurolite Staurolite showing internal inclusion fabric, in schist. The thin section contains many small, inclusion poor grains of staurolite, which is a high relief mineral pleochroic with colours ranging from pale yellow to almost colourless in plane polarised light, and with low birefringence colours in crossed polars. It ranges from transparent to opaque in diaphaneity. Kyanite (high relief, cleavage) Staurolite Return to index minerals Return to introduction, Mineral structure: Single SiO4 structure, Common mineral in Pelites (Schists & Gneisses) Although commonly light yellow-green in thin section, it may be colorless. Staurolite often occurs twinned in a characteristic cross-shape, called cruciform penetration twinning. Staurolite is a metamorphic mineral that is found almost exclusively in medium-grade schists. Key optical features of staurolite in thin section: Pale Yellow Moderate relief No cleavage, common fractures Low-Moderate order interference colours. Staurolite - (Fe 2+,Mg,Zn) 2 (Al,Fe 3+,Ti) 9 O 6 [(Si,Al)O 4] 4 (O,OH) 2 The name "staurolite" is from the Greek word "stauros" which means "cross". Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. Return to index minerals introduction Magnification: 40x To see this mineral in XPL, click here: https://youtu.be/O2gvC6wvqEg To…, Staurolite in crossed polars. The mineral commonly occurs as twinned, six-sided crystals that sometimes intersect at 90 degrees to form a cross … Share. Staurolite has parallel extinction and one cleavage parallel to its length, and has a characteristic pale to darker golden yellow pleochroism. General Staurolite Information : Chemical Formula: (Fe++,Mg)2Al9(Si,Al)4O20(O,OH)4 ... Minerals in Thin Section-University of North Carolina 17 - Minerals in Thin Sections-Humboldt State 18 - Online Mineral Museum 19 - QUT Mineral Atlas 20 - Ruff.Info 21 - Scandinavian mineral gallery Staurolite in muscovite staurolite schist, Staurolite in  plane polars Staurolite at mindat.org, Staurolite in muscovite staurolite schist. Search for Staurolite using: 16 - Minerals in Thin Section-University of North Carolina 17 - Minerals in Thin Sections-Humboldt State 18 - Online Mineral Museum 19 - QUT Mineral Atlas 20 - Ruff.Info 21 - Scandinavian mineral gallery 22 - UCLA - Petrography Thin-Sections 23 - WWW-MINCRYST 24 - theimage. In general, it has an isolated tetrahedral structure related to that of kyanite. Plane-polarised light, field of view 1 mm. In hand sample, staurolite frequently occurs as twinned prismatic crystals known as “fairy stones” or “fairy crosses.” In thin section, it displays a poikiloblastic texture which people often liken to vomit spatter—gross, but effective. The mineral often forms porphyroblasts.. Rock-forming minerals of metamorphic rocks, in thin section (a work in progress) Atlas of Metamorphic Minerals. Occurrence: Staurolite is found in medium-grade pelitic metamorphic rock, and is used as an index mineral in metamorphic zoning. The crystals are brown, red or yellow in color. Garnet (isotropic, high relief), Twitter. This example has a twin, highlighted by different color and birefringence caused by its different orientation. Andalusite (colourless, cleavage), Note: Complete or partial alteration to fine grained muscovite around margins and along fractures associated with influx of fluids. Magnification: 40x To see this mineral in PPL, click here: https://youtu.be/ppJP74V6Z88 To explore this slide in PPL, click her…, Staurolite at webmineral.com Associated with medium pressure, medium temperature metamorphism, Rock-forming minerals associated with Staurolite: Biotite, Muscovite, Quartz, Garnet It is usually brown or black in color with a resinous to vitreous luster. In hand sample, staurolite frequently occurs as twinned prismatic crystals known as “fairy stones” or “fairy crosses.” In thin section, it displays a poikiloblastic texture which people often liken to vomit spatter—gross, but effective. May resemble tourmaline in thin section, but tourmaline is uniaxial. See more ideas about minerals, geology, metamorphic rocks. This example has a twin, highlighted by different color and birefringence caused by its different orientation. In handsamples, macroscopically visible staurolite crystals are of prismatic shape. Return to introduction. Note: Staurolite typically displays grey-yellow interference colours. Staurolite in crossed polars, Staurolite displaying its characteristic yellow-brown pleochroism. Properties of Staurolite. Staurolite thin section. In thin sections staurolite is commonly twinned and shows lower first order birefringence similar to quartz, with the twinning displaying optical continuity. Email. Staurolite has parallel extinction and one cleavage parallel to its length, and has a characteristic pale to darker golden yellow pleochroism.