Hi Jack,
The way I can tell you for sure it's jatoba is because of the particular grain like in maple... No rosewood has the "line of growth rings" visible on the side of the wood. Only maple and fruit trees have 'em...
Jatoba is pretty stable when dried properly and can be used as forearms, buttsleeves or handles.
Angico, also known as indian chestnut, is not a "fruit" wood and could be considered as being a similar wood more like oak. Like oak, it's always better to core the wood as the grain is very long stretched.
It's hard, keeps it's figure no matter if you rift saw it or quarter saw it.
It's dense and heavy and finishes pretty well.
One tip: if you use that wood, seal it before polishing it. That way, the sealer will be absorbed better and the finish will deepen more the color and figure of the Angico.
Good luck using it...
Send me some pics when that cue is finished please
Tom Penrose