ill add mine to the thread:
stainless steel sphere, blue bronze finish, laser 6MT etching, 2 grooves on the bottom of knob (gives an awesome feel IMO), and matching metal bronze collar. total weight is around 520 grams
crappy phone pic though
and to add to the discussion, weight totally matters on the Z. our clutch is kinda knotchy and when i used my previous knob...that was 1/3 the weight, shifts would sometimes miss and not fall into place completely, and a variety of little things if you werent careful.