Hey,
I was wondering this myself so I stopped by my dealer in Taiwan to try something that has always caught my eye. A beautiful white jade cup.
Short story is, jade is pretty to look at but awful for tea. This is white jade, probably the most expensive kind and it made tea taste chalky and extremely heightened. Very unpleasant and also incredibly difficult to hold as it gets extremely hot.
Re: About Jade as a teacup material
I've got a jade teapot and really like its appearance as well as using it. 
