Rock-forming minerals of metamorphic rocks, in thin section (a work in progress) ... 32 Staurolite Staurolite showing internal inclusion fabric, in schist. In general, it has an isolated tetrahedral structure related to that of kyanite. The crystals are brown, red or yellow in color. Staurolite has parallel extinction and one cleavage parallel to its length, and has a characteristic pale to darker golden yellow pleochroism. 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. Staurolite is a metamorphic mineral that is found almost exclusively in medium-grade schists. See more ideas about minerals, geology, metamorphic rocks. Although commonly light yellow-green in thin section, it may be colorless. Twitter. Note: Staurolite typically displays grey-yellow interference colours. Key optical features of staurolite in thin section: Common minerals that might be confused with staurolite and occur in similar rocks: Staurolite often occurs twinned in a characteristic cross-shape, called cruciform penetration twinning. Staurolite in muscovite staurolite schist, Staurolite in plane polars Email. Other index minerals commonly associated with Staurolite: Kyanite. The mineral often forms porphyroblasts.. Magnification: 40x To see this mineral in XPL, click here: https://youtu.be/O2gvC6wvqEg To…, Staurolite in crossed polars. 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 Staurolite's hand sample has characteristic penetration twinning and unique crystal habit. Staurolite at mindat.org, Staurolite in muscovite staurolite schist. 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. Facebook. 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. Staurolite has parallel extinction and one cleavage parallel to its length, and has a characteristic pale to darker golden yellow pleochroism. 1952. Garnet (isotropic, high relief), Note: Staurolite typically has short prismatic habit and frequently contains quartz inclusions, Return to top Associated with medium pressure, medium temperature metamorphism, Rock-forming minerals associated with Staurolite: Biotite, Muscovite, Quartz, Garnet It ranges from transparent to opaque in diaphaneity. It is usually brown or black in color with a resinous to vitreous luster. This example has a twin, highlighted by different color and birefringence caused by its different orientation. Oct 2, 2020 - Explore Bryn Mawr College Mineralogy's board "Minerals in Thin Section", followed by 119 people on Pinterest. 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.