Are you talking about Primos "slick stick" 5 in one conditioner with stone? That is the only "stone" I see that Primos makes to condition friction calls.
That's what I'd recommend. I got one for this season and it is very convienent and does a good job. This is the 3rd year I've had my power crystal and it sounds great and seems to need to be sanded less than the previous years. One thing I've found is to be careful not to touch the calling surface when getting call out of your vest, as the oils in your fingers will hurt the surface of the call.
Mine sounded the best with the purple heart striker too until I got a guy at work to turn some strikers for me and he made one from cherry. That made the call sound the best I've ever heard and I'm really looking forward to using it this year. Only 8 more days and a wake up.
