"The technology, Pyrophyllite-SiC-C Unfired Brick , was awarded as a second prize of Science and Technology Achievement Award in 1992 in Nov ., 1992.
22.
It occurs in association with attakolite, svanbergite, lazulite, hematite, trolleite, berlinite, rutile, pyrophyllite, baryte, arsenopyrite, stannite, pyrite, andorite, cassiterite and zinkenite.
Although potentially stable at lower pressure and low temperature, the activity of water is usually high enough under such conditions that it is replaced by hydrous aluminosilicates such as muscovite, pyrophyllite, or kaolinite.
25.
Pyrophyllite, a mineral very similar to talc, is sometimes called soapstone in the generic sense since its physical characteristics and industrial uses are similar, and because it is also commonly used as a carving material.
26.
In South Africa, major deposits of pyrophyllite occur within the Ottosdal region, where it is mined for the production of a variety of manufactured goods and blocks are quarried and marketed as " Wonderstone " for the carving of sculptures.
27.
The 2 : 1 clay minerals ( pyrophyllite-talc ) consist of T-O-T stacks, but they are softer ( hardness from 1 to 2 ), as they are instead held together by van der Waals forces.
28.
It includes varieties of andesite, argillite ( slate ), basalt, bluestone, breccia, greenstone, labradorite, limestone, marble, melaphyre, pitchstone, pumice, pyrophyllite, quartz, quartzite, sandstone, schist, serpentinite, shellstone, soapstone, syenite, travertine, and tuff.
29.
This variety, when heated before the blowpipe, exfoliates and swells up to many times its original volume, hence the name pyrophyllite, from the Greek " pyros " ( fire ) and " phyllos " ( a leaf ), given by R . Hermann in 1829 . The color of both varieties is white, pale green, greyish or yellowish; they are very soft ( hardness of 1 to 1.5 ) and are greasy to the touch.
