Kyanite, Al2SiO

In aluminosilicates, too, including epidote and the Al2SiOs polymorphs andalusite, kyanite and sillimanite, Al3+ ions occupy several coordination sites. Again, trivalent cations such as Cr3+, V3+, Mn3+ and Fe3+ may show cation ordering and be relatively enriched in one specific Al3+ site in a crystal structure. 

Aluminum silicate, andalusite (Al2SiO ) Aluminum silicate, kyanite (Al2SiOg) Aluminum silicate, sillimanite (Al2SiOg) Aluninum sulfide (AI2S3)... 

X-Ray powder data and i.r. spectra have been reported for the kyanite phases Al2SiOs and AljGeOj, synthesized at 20kbar and 1000 °C."""... 

Also known as bauxitland cement. Kurlbaum Method. A method for the determination of flame temperature by means of an optical pyrometer (F. Kurlbaum, Phys. Z., 3,187,1902). Kyanite. A mineral having the same composition (Al2SiOs) as sillimanite and andalusite, but with different physical properties. The chief sources are Virginia and S Carolina (USA), and India. When fired, kyanite breaks down at 1300°C into mullite and cristobalite with a volume expansion of about 10% it is therefore calcined before use. Calcined kyanite is used in making aluminous refractories. 

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