Petoskey Stone Shapes

You might want to look through this recent thread forum.rocktumblinghobby.com/thread/104857/lapidary-diamond-band.  That said, I have cut Petoskey stone slabs on a 10-inch diamond blade trim saw.   realrockhound mentioned water fed.  That is probably better than oil for Petoskey stones.  I have always used oil because it seems to work better for harder material and I haven't gone to the effort of changing to water for softer stones. 

Petoskey stones can be a lot more porus than other rock materials and you may get a lot of oil soaking into the slab you are cutting.   This hasn't been an issue for me but you should know that the oil will change the appearance of the stone (will tend to make it darker and look more like it does wet which is good from an appearance standpoint).  However, as the oil evaporates, the slab or shape may return to the "not dry" look.   If you have a high quality Petoskey stone, the finished polished look (assuming you are going to polish the shapes) will look good regardless. 

There are also ways to make the oil (wet) "look" be more or less permanent for Petoskey stones.    Submerging the stone in food grade mineral oil (from grocery or hardware store) and baking at 200F for 2 hours will give you that "wet" look for a long time.  I have been doing this on some lower quality Petoskey stones for more than 2 years and the wet look doesn't seem to go away.   I haven't sold any treated stones so haven't been concerned about "altering" the appearance this way.   Also, the oil baking method won't do much for a really low quality Petoskey stone.