I have a buddy who repairs, refurbishes and appraises swords for museums. He showed me a number of them when I was at his place one day. One was worth around $60K, and it wasn't even the one with the nicest hamon and figure in the blade. Having the chance to look at various temper lines (hamon) and the figure of the steel's weld patterns was really neat. I can see how people get into just looking closely at the blades for a long time. Some blades have a very fine wood grain type of figure in the steel from all the laminations.
Way out of my league though. I had to wear cotton gloves, and hold a folded cloth in my mouth while handling them.