I think it is just a fancy name for a certain look. At the end of the day eastern red cedar is eastern red cedar. There is a difference in the woods look depending on weather it was open grown or grown under a forest canopy. You tend to get this "marble cake" look more from wood grown slowly or under a canopy than open grown. In my experience open grown tends to not have the blending of the sap and heart woods. I have cut up a lot of eastern red cedar. Hope this helped
Travis