Based upon what I have seen and been told, there are two types of Tulipwood. Blank #4 certainly looks like Brazilian Tulipwood, which is generally a light colored wood with bright reddish grain lines running through it. The other type of Tulipwood grows in the eastern U.S. It can either be light or dark, but is more "creamy" in texture (if that's an appropriate description.) Because the rest of the group has the well defined reddish grain lines, I would say that its all Brazilian Tulipwood. Personally I have not seen any that is this dark before, so perhaps another with more experience can chime in. One thing I can say is that Tulipwood makes great pens, IMHO.