Kaolinite and dickite occur at lower temperatures whereas pyrophyllite and andalusite occur under high temperature conditions ( T > 300�C ).
12.
These two groups of minerals are subgrouped by octahedral occupation; specifically, kaolinite and pyrophyllite are dioctahedral whereas serpentine and talc trioctahedral.
13.
Talc is a trioctahedral layered mineral; its structure is similar to pyrophyllite, but with magnesium in the octahedral sites of the composite layers.
14.
Under low-grade metamorphic conditions, kaolinite reacts with quartz to form pyrophyllite ( Al 2 Si 4 O 10 ( OH ) 2 ):
15.
Originally, pyrophyllite was quarried and locally used for tombstones and building stone and to carve ornaments and utensils such as pots, dishes and cases.
16.
"' Pyrophyllite "'is a phyllosilicate mineral composed of aluminium silicate hydroxide : Al 2 Si 4 O 10 ( OH ) 2.
17.
Minerals formed by alteration processes include alunite, calcite, cristobalite, illite, jarosite, kaolinite, pyrophyllite, quartz, smectite, sulfur and tridymite.
18.
Typically the gasket material used is pyrophyllite, and the mullite will be machined into a sphere which sits in pyrophyllite seats , forming a cube.
19.
Typically the gasket material used is pyrophyllite, and the mullite will be machined into a sphere which sits in pyrophyllite seats , forming a cube.
20.
The minerals are feldspar, ball clay, bentonite, pyrophyllite, calcite, gypsum, phosphate rock, quartz, coal, dolomite, gemstone, tin ore, and manganite.
