I think dymondwood is impregnated by using a vacumm and and actionwood is just strips of dry hardwood pressed together. The impregnation of resin into the wood fibers of the dymondwood probably give it the brittle chipping characteristic that you saw. The actionwood wood fibers not being impregnated with resin retain the natural durability of wood. They can use a variation of types of hardwoods. Mostly birch for actionwood I think.