Sometimes the Carrara/Calacutta/Statuario stones like this will burn and orange peel and there is nothing you can do about it. other times they will be nice and glassy. The line between variations of these stones is so small, you often can't tell until you're nearly done.
Dynamite isn't that hot, but you said you're using a felt pad? Like a firm, dense felt pad, not a white nylon pad? If so, that could be your problem. Felt pads generate too much heat.