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Mg2(Al4Si5O18) A blue, orthorhombic magnesium aluminosilicate mineral frequently occurring associated with thermally metamorphosed rocks derived from argillaceous sediments.



[named for French geologist P. Cordier (1777–1861)], also iolite or dichroite, a mineral, a complex aluminosilicate of aluminum, magnesium, and iron; chemical composition, (Mg, Fe)2Al3[AlSi5O18]. Its crystal structure is characterized by a ring construction similar to that of beryllium. Cordierite crystallizes in the orthorhombic system. It occurs in the form of prismatic crystals, irregular clusters, and grains of blue-gray, blue, violet, or brown color; sometimes it is colorless. It has a hardness of 7.0–7.5 on the mineralogical scale and a density of 2,600–2,660 kg/m3. Dichroism is a characteristic feature and is highly pronounced in transparent grains. The mineral effloresces easily to form talc, mica, and other secondary minerals. Cordierite is formed during contact metamorphosis of rocks rich in aluminum and magnesium. Transparent varieties of cordierite are used as gems.

References in periodicals archive ?
Compared to DPFs made of other materials, cordierite DPFs are light and provide lower pressure drop of exhaust gas resulting in high engine performance and efficient purification.
Uskokovic, "Synthesis and Formation Mechanism of Submicrometer Spherical Cordierite Powders by Ultrasonic Spray Pyrolysis," J.
The astronauts collected their samples near the moon's huge Imbrium basin, and the researchers suggest the cordierite bit was "excavated" by the same impact that formed Imbrium.
However, scattered lenses of pale metasiltstone show a smaller proportion of cordierite porphyroblasts than their matrix, and contain visible laminae of pale metasiltstone that are folded in open to tight folds (Figs.
Typical high temperature non magnetic minerals found in pyrometamorphic rocks associated with coal combustion appear to include several Fe and Al rich clinopyroxene, melilita, cristobalite, tridymite, mullite, cordierite and fayalite solid solutions, as well as glass (Foit et al.
The Southwestern Group consists of cordierite granulite facies rocks made of cordierite gneisses, calc granulites, and metasediments.
The main rock types of the zone are Al-rich gneisses (with biotite, cordierite, garnet, and sillimanite) and biotite-plagioclase gneisses; less abundant are amphibole gneisses, amphibolites, and quartz-feldspar gneisses.
The metamorphosed alteration zones are characterized by the presence of various combinations of anthophyllite, cordierite, garnet, staurolite, biotite and/ or andalusite.
Geothermobarometry of the Bi + Gr [+ or -] Sil assemblage and cordierite suggests peak metamorphic conditions at 600-700[degrees]C and 3-5 kbar (Klein 1986; Koistinen et al.
Talc products are also being extensively used in vehicles for manufacturing and processing cordierite bodies for catalytic converters.
K-feldspar is stable, muscovite is present only as a retrograde mineral, garnet is very rare, and cordierite occurs in both mesosome and leucosome.