I was in my local music shop today and I grabbed a dusty Ibanez off of the rack and started to thump on it. The bass sounded very nice and I noticed that the strings were very odd- they were round wound but it looked like one strand was nickel and the other was dark-green in color (nylon? Or colored steel?). The gauge was pretty thick and I asked the sales person what kind of strings they were and he had no clue. Any ideas?