Here are some links you may find interesting. Each one was a source of information for this website so if you want more information I suggest you start with these!
http://mineral.galleries.com/minerals/silicate/talc/talc.htm
http://www.maxfactor.com/uk/frameset.asp
http://www.bris.ac.uk/Depts/Chemistry/Bristol_Chemistry.html
References;
Clay mineralogy /Ralph E. Grim. 2nd ed.. New York : McGraw-Hill, 1968
The X-ray identification and crystal structures of clay minerals. [2nd ed], edited by G. Brown.. London : Mineralogical Society, Clay minerals Group, 1961.