Yerllowheart from Brazil, has a very tight grain I have seen results with it in pens ,has a mild smell can cause allergies.
Greenheart suffers from grain tearout, comes from Nth and Sth America ,hard to glue,stiffest wood in the world.
It would seem in common with many timbers to try for cut blanks, also there are so many easier and better timbers IMHO.
Peter