Sillimanite has been found in Brandywine Springs, New Castle County, Delaware, US . It was named by the State Legislature in 1977 as the state mineral of Delaware by suggestion of the Delaware Mineralogical Society, Inc.
32.
Andalusite has the second aluminium in five-fold coordination ( Al [ 6 ] Al [ 5 ] SiO 5 ) and sillimanite has it in four-fold coordination ( Al [ 6 ] Al [ 4 ] SiO 5 ).
33.
Kerala Minerals and Metals ( KMML ), a Government of Kerala undertaking located on the beaches of Shankaramangalam ( Chavara ), produces high-grade chemical compounds of titanium such as titanium dioxide pigment, hafnium ore, sillimanite and monazite.
34.
The remaining Al 3 + can be in six-fold coordination ( kyanite ), five-fold ( andalusite ) or four-fold ( sillimanite ); which mineral forms in a given environment is depend on pressure and temperature conditions.
35.
Andalusite, kyanite, and sillimanite are naturally occurring aluminosilicate minerals that have the composition polymorphs is located at a temperature of 500 �C and a pressure of 0.4 GPa . These three minerals are commonly used as index minerals in metamorphic rocks.
36.
The highest-grade rocks ( kyanite and sillimanite gneisses ) are found within the MCT shear zone, i . e . upper Lesser Himalaya . places two thrusts ( MCT I and MCT II ) on each side of the MCT shear zone.
37.
Apart from producing rutile-grade titanium dioxide pigment for various types of industries, it also produces other products like ilmenite, rutile, zircon, sillimanite, synthetic rutile etc . It is one of the best performing Public Sector Units in India.
38.
Another example are the aluminosilicates kyanite, andalusite, and sillimanite ( polymorphs, as they share the formula Al 2 SiO 5 ), which differ by the coordination number of the Al 3 +; these minerals transition from one another as a response to changes in pressure and temperature.
39.
Among accessory minerals, in addition to apatite, zircon, and iron oxides, the following may be mentioned : hornblende ( not common ), riebeckite ( rare ), epidote and zoisite, calcite, sphene, andalusite, sillimanite, kyanite, hercynite ( a green spinel ), rutile, orthite and tourmaline.
40.
In addition, G . G . Rusanov found malachite, axinite, sillimanite and cinnabar in the schlichs of the ripple marks in Kuray Basin, which are characteristic of the Kuray Ridge but not found in the schlichs of the end moraines of the Tetio River, the latter adjoining the fields of the giant ripples.
