I sell Dogwood pen blanks (when I can get the wood) and have never encountered a hunk as hard as you describe. Most of it is just wood, no particular problem turning. I even had a very large hunk given to me. It had been dry stored for years. Not particularly hard. Dogwood is hard come by as most folks don't like ornamentals cut down and it usually doesn't get very big. Pen with cross clips are very popular as are wall hanging crosses. The legend of the Dogwood says that the cross Christ was crucified on was made of Dogwood. No biblical support, just from an old poem but people like the connection.
"Folks is funny critters."
Think for yourselves and let others enjoy the privilege to do so, too. ~Voltaire