What tree species is South American Ironwood???? So many different woods are referred to as "ironwood" that the term is almost meaningless. Among them are Osage Orange (also called hedge apple and ironwood), Lignum Vitae (which is South American and might be what you are referring to) and then there is Texas Ironwood, which is yet another species. I have recently commissioned
Martin Brunkalla to make me a bow of an American hardwood of his choice, which will probably be either Texas Ironwood or Osage Orange. Lignum Vitae is probably not limber enough and it has some internal oils that make it great for bearing seals on ship propellers, etc. but make it nearly impossible to glue in any normal way. It is also used for mallet heads.
Then again it could be some other South American wood that you refer to. Ipe is also very hard and has been used for bows. 190 grams is really heavy. There are not very many woods denser than ebony or Lignum, so that may be the way to go if you can find a maker that will do that for you.