Can kidney stones be black? My husband passed one that was black and as big as a watermelon seed. does that sound right. He s had kidney pain for almost a year now but not since he passed it. He had urinating pain a few weeks before passing. Also, the pain in the past seems to have corallated with him working hard and/or sweating in the sun all day. We thought it was from drinking too much pop. He has been drinking more water lately. Maybe that s why it suddenly came out.