Soap stone / talk are one in the same I have turned a few bits in it and as said it turns to powder talcum powder in fact so you can talk your bum after
Right a small bowl first stick the stone to a sacrificial bit of wood and mount that on your lathe dont try and mount the soap stone direct to the lathe because it isnt that strong and chances are it could split under pressure when finishe part it from the wooden disk don some rubber gloves because you could end up with some sort of skin complaint I did also protect your breathing as this stuff it is suspected can cause cancer
turn using a scrapper is best I have found but most turning tools will cut into it sand and polish the same as you would plastic I have attached some picks
Done it in wood after all that well I dont know still you have it for when you do it LOL bloody plonker Huh