Pen that writes without ink

Using a solid metal nib made of an alloy that leaves marks as easily as lipstick (but wearing down so infinitesimally slowly that it might as well be solid diamond you're scratching your initials into everything with) this pen never needs a replacement cartridge - it's just a stick. So get a nice one; your great-great-great-great grandchildren will be able to use it as well as you can (though they probably won't know what a pen is). [GT]

Metal pen [Spluch]