pyrophyllite
Instance URI: http://resource.geosciml.org/classifier/cgi/commodity-code/pyrophyllite
Within scheme: South Australian Commodity Codes
A phyllosilicate mineral composed of aluminium silicate hydroxide: Al2Si4O10(OH)2. Pyrophyllite is easily machineable and has excellent thermal stability and is added to clay to reduce thermal expansion when firing and is combined with other compounds, such as in insecticide and for making bricks. It is also used for slate pencils, chalk (French chalk) and small carving.