I put down a bluestone patio and had no unusual discoloration, some light
reddish brown, blue gray, gray, etc. Normal to me. About 2 weeks after the
job was completed a couple of the stones seem to be browning and leeching a
brownish substance to the joints. Pressure washing prove to take the
discoloration off the joints, which said to me it was not migrating from
below. The stone seemed to clean a bit. Another 2, or so weeks past and the
same situation has occured. I'm stumped. Any help is appreciated. Thanx,
Mike.