I just got one of these HMC5983, it is a new version of the HMC5883 magnetic sensor, it seems to be identical, the same sketch runs without modification.
It appears to be capable of using SPI in addition to I2C, but I would have to alter the track on the breakout board, which I am not going to do right now just to find out, I have had enough soldering aggravation for this week.