Many old-timers still use Almag or Pella oil, which is stinky and causes rashes on sensitive skin. We use a special grade of white oil that has a high flash point, has absolutely no detectable odor and is kind to your skin. It does at least as good a job of cooling and lubricating as Almag and Pella oils. An added benefit is your slabs don't have the nasty smell of the old-style oils.
Oil coolants are for heavy duty cutting and provide the greatest protection for your blades. The other advantage of using oil as a coolant is it can be left in your saw without the worry of rusting your blade. If you cut agates, this is the coolant for you.
We carry two brands of oil: Lapidary Oil and Covington Rock Hound Oil. They are the same thing with different labels. The one gallon containers of Lapidary Oil are easier to handle than the 5 gallon bucket of Rockhound Oil, but are more costly per gallon.